I think that I finally appreciate how roll angles can mess up a rig if not handled properly so the question is, how are they optimally set?
For example you have a person who has a spine going up and down but the legs pointing down, if you use Z axis as up, do you rotate the roll for legs so Z points down? So what about x and Y then which way do you want them to face?
What about arms - they stick out at 90 degrees but which way are you placing the palms and elbows relative to the bone roll angles and corrdinates?
Please help me avoid mistakes.