I'm wrestling with some of the concepts on the face. The seams are including the neck in the face island and that, by the color yellow and some orange on the nose, indicates it needs some work plus the nose needs work because it bulges and stretches the tiles. Having both the neck and face seamed together seems to make it harder to find room to manipulate points. Is there a reason the neck isn't seamed seperate to give more room to work the face? If it is skin texture, which in most cases on a stylized character is fairly consistent, would any seam made under the chin even be noticeable? I can see a realistic character where you may be texturing wrinkles have a seam be a big issue but would that even be an issue with a simple texture like on Snow or Rain?

how do you get good skin color

I'm going through this tutorial, over and over, to get my head around the system before going to the next tutorial. I know there are multiple ways to accomplish the same task so, a few more questions.

Ok, let me try that again. 1. When unwrapping, you mention that you are trying to get the stretching/spacing to indicate blue-green-yellow-orange-red in that order in area stretching, ideally blue but, you isolate parts like the head and scale them to fill the entire image to work on. Just about everything goes to yellow, isn't scaling up like that throwing off your image?  If keeping the stretching in a blue indicator is ideal, shouldn't I just rely on zoom to work the adjusting? 2. You start working the head with the mirror modifier on, giving both halves of the head to work on, which would be tough to keep halves coordinated. Later you kill the mirror modifier off, work the halves in place on the UDIMs, again at different scales, then duplicate the patterns with the mirror modifier being applied, seems like unnecessary to activate the mirror modifier till the end.   Would there be a downside to just working with the half of the mesh with the mirror modifier not applied?  3. You treated the mouth the same way as the eye, breaking it away from the head. Would the same thing be achieved by putting a seam around the mouth in the first place, like on Rain?

One other thing, I noted when working on the closed eyes you mentioned at about the 52 minute mark that you wanted to first add a shape key to close the eye so, I did that first to avoid manipulating everything later like in the tutorial...turns out, you can't do that. At the very end, I had everything laid out on the UDIMs and couldn't apply the mirror modifier - because there were shape keys. So, might want to edit that video a bit because it makes for a lot of rework, maybe just an audio correction when you say "shape keys", change it to "close the eyes".

I started putting the shape keys on the character. The eyes and mouth open work fine. When I put the shape keys on the teeth and the tongue to rotate with the mouth opening, they don't respond, with or without it being set with driver. I tried a number  of combinations then opened a new job, deformed a cube and the shape key worked, then I set a shape key for just rotation on a different new cube, like the tongue and teeth would use, that wouldn't rotate. I watched that part of the video over and over thinking I missed something but the teeth and togue being separate objects don't. I'm using version 3.3.1

Also, in the secondary key (mouth-open) on a set of teeth standing by themselves, I moved just one pixel out, to see if that was what was needed to trigger the rotation but, when I go between the keys, the ending angle stays the same and just the pixel moves so, the keys and/or driver, isn't picking up rotation of the object. Is this a bug or, is there another setting that is in 3.3.1 that isn't in the 3.0 the tutorial was made of, or, is it a bug?

OK, I've tried every combination on the teeth to get the shape keys to work and nothing works. I tried creating the Basis with the teeth together and the "mouth_open" with the teeth rotated down like the tutorial but, changing the value slider from one to zero has no effect on the rotation. I tried copying the driver from the body, which does work opening the mouth, then pasting on the teeth/tongue, the value turns purple indicating it is attached but when I go back to the body and close the mouth the teeth do not follow, the value does not change either. I went back into the Rain V2.4 model and activated that shape key and tested and it works there. So, back to the character I'm working on (which started with the rain basemesh) and went into the driver editor, there is a driver there but, it just does not connect from the body "open_mouth" to the teeth "open_mouth" . I've been all over the internet looking for an answer but can't find or get one so, I've spent the better part of two days on just that shapekey trying to find a way to make it work and I'll have to skip this section and assume version 3.3 has a shapekey bug. I've also tried this process with the cube both with the shape of the cube changing and a rotation and the shapekey doesn't acknowledge the rotation there either. What stumps me is when I pull up the Rain v2.4 in version 3.3, that "mouth_open" shapekey works on the teeth but, if I add a cube next to Rain, change position of one vertices then rotate the unit a bit, copy the driver from the body to the cube andthe teeth rotate but the cube doesn't using the same driver. So, I looked at whether the shapekey in Rain v2.4 was running on the original shapekey script it was created in a few versions back by deleting the shape keys on the teeth to clear the old code then adding them back the way you have in the tutorial...they didn't work there, the rotation isn't connected to either the value before the driver or after the driver is added. Given that I tried entering the keys and drivers in every permutation, including turning on and off the keys, I'm guessing it is a bug.

I kept wrestling with the teeth opening and, in the tutorial you are creating a driver from the open mouth and using it to open the teeth objects. Apparently that does not work in 3.3, the driver will not rotate an object. So, the only way around that I was able to come up with was to take the upper teeth and gums and create separate vortex groups so I could more easily color the teeth separate from the gums, I did that for the lower also. I didn't want to stack up drivers so, with the vortex groups set, joined the geometry of the upper teeth/gum and lower teeth gums, leaving me two objects instead of four. Then I joined the geometry of the lower and upper. This gives me one object but, with the vortex groups, I'm able to separate the upper set from the lower easily by "select" vortex group. Now, with all the vertices in the same object, with the body mouth closed and teeth closed, I selected the teeth/gum object and added two shapekeys, the "basis" and "mouth open",  then went back to the body object and opened the mouth, back to the teeth object, selected the mouth open shapekey,  and used the vortex groups to easily select just the bottom teeth/gum setup, rotated that down. Then back to the body, created the driver for the mouth open, back to the teeth/gums and selected that "mouth_open" shapekey and pasted the driver.  That worked. It is going way around the horn to get the same result as in the tutorial.

So, if a shape key only applies to vertices in the same object in 3.3, allowing rotation and axis position to change only by editing the vertices directly in an object edit mode, are there other options for a driver in one object to manipulate rotation and position of another object? This would be common in making mechanical gears turn to bring life to machine models.