There is always an exception to any rule
I'd just minimize stretching (to a certain degree) since it'll make texturing easier.
I usually do the UV mapping by hand; I just split the model into segments and then do the default UV unwrap (or smart unwrap if the default UV is fucked up). Then I just modify the UV areas by hand and make them perfect in my opinion so they use as much of the texture area as possible while still having relatively good stretching.
Whatever looks best and whatever you feel good with is best
Keep up with the good work
PS.
The easiest way to do hands is to split the bottom part of the hand (think of black man's hand, the piece that is white is a separate area)
Also split the hand around the wrist.
Then you could just split the arm on the bottom side and when you UV unwrap that it should turn out to be a rectangle shaped UV.
Same for the feet, make the bottom of the feet a separate UV area and the top of the foot another, Split the leg on the inside and unwrap that to a rectangle.