Im a freelance photographer, but never tried. Only for jobs that i can take photo of pretty girls, but of course, i always try to take a few 走光photo of the models for my own collection =)
I did it a few times too. Just in case anyone is wondering, 私影 is just a photo shoot. Don't expect that the girl will have sex with you after. I think its different in Asia where 私影 is almost just a cover for sexual transaction. Here is different, some 龍友s have gotten into deep trouble for their mistaken assumptions.
I'm interested and I have done a few small projects for fun. If you are getting into studio setup or need some pointers, let me know. I have not used my studio setup for a while since I mostly do weddings now.
I personally wouldn't mind to work for free depending on what you have in mind . Like a themed photoshoot with some planning.