The key to a good brazilian wax is to make sure the skin is as tight as possible. This means making your clients do the stretching. For the pubis mons I get the client to lay their hand flat on their tummy, right above the patch of hair, and pull as tight as they can towards their belly button. Then I apply the wax from the top of the hairline down to where it meets the top of the labia. I only do this only on one half. (do the other side after). When I do the actual labia, I get the client to lay their hand flat on the pubis mons and pull towards their belly button. With their knee bent and to the side. I apply the wax from the perenium up about half way on the labia, then remove. Then I do from the top of the labia down. I always tell my clients... the tighter you pull, the less it hurts!! Also, I never allow them to leave any clothing on (from the waste down). Having disposable undies, or their own undies only hinders my ability to get in and get the job done thoroughly. I tend to use a lot of oil when I'm doing genital waxing.
Oh, and to answer your question about removing the hair on the inside of the labia, apply a generous amount of oil, and wax away!!
HTH.