Again, I am no expert, but I would suggest giving the most prominent areas of your model the most amount of UV space. Though resizing won't really affect your texture if you're just trying to get it to fit. The best bet is to assign a checkered shader or some other patterned shader so you can see if you have any stretching when you are laying out the UVs.

I like the drawing! And I see what you mean about the wrist area. This should look cool once it's textured.