Yo all these hands look sick! Funny how I used to hate drawing hands because they just felt too hard, now it's actually fun to tackle them. These all look very detailed and smoothly shaded.
For the color theory observation... yea, I actually where I need to do 3 more of it... and I kinda groan a bit about it. Like, identifying the palette is fine, and I think that's what I'll do, but elaborating notes ain't that much fun. Still, I'll be a good boy and complete them as well. I see you noted that the key color usually has the highest contrast, and while I think that's true, I think high saturation is also used for accents.
Also love the muscles over bones exercies. Agreed that iwas more fun than the previous ones. Muscles in general are very interesting. Not much I can say there, they all look fine to my eyes, some have muscles a lot more exagerated, but I think it's clearly due to the syle, like most from the back seem to have shorter Lats and longer obliques and erectors, but the form and placement seems correct and I really think it's just due to style.
Btw I love that style.
Hope you feel better and burn down. I totally get what that feels like and yea, it's no fun.