Question - Do people kip or dead-hang?
that varies from person to person, diskill, depending on your situation. if your set-up doesn't allow it, obviously you'll not be able to kip.
if you purely want to concentrate on form, it would be better to do dead hang's. kipping really comes into effect on D3, where you say you have to do 10+ pull-ups - it will allow you to do the pull-ups quicker, without "cheating".