What is the best time to belly paint?

I have 3 momma's to be lined up to belly paint, and not sure the best time to paint them? This is a first for me, so I am super excited, was hoping for some direction on the best time (7 months, 8?) Also, for those of you who have painted many a belly, is there any tricks I need to know about. I was thinking about placement, and warping a flat design around a round tummy... anything I should know? Any help greatly appreciated! Thanks!

when the person is sitting in front of you, keep in mind the belly wil 'drop' (when they get up) and it could mess up your drawing... (out of wack)
and I recomend between 32 and 36 weeks... depending on how they carry.
some are already big in the beginning, some are not, so play it by ear...

and spray the belly with hairspray to fix the paint. make sure your nog spraying to close, it will water of your paint, so not to much and from a distance...

Good luck with the bellies... Hope to see picks soon!