Im not sure why you feel off balance when putting bodyweight into combinations, rather than a transfer of weight from 1 leg to another its more like transfering weight from an evenly distributed stance so that more weight is distributed to one leg than the other but the other leg is not totally relieved otherwise you risk loseing balance, if i was you i would check out the useful threads section and at the top theres a thread with tons of info and free e-books etc, it seems to me that maybe your form is a little off and maybe looking up the basics again and refreshing things might help, im sure some more experienced boxers will have more info uve come to the right place balance is everything in boxing.