Damn, you got a good set-up going on. The curtain thing is Panda film. Comes in a big roll and is the shit. Keeps light out where you need no light to be. Yeah, my girls are looking real good. My first grow, btw. Can't wait to harvest them. I hate using seeds, but sometimes you gotta use 'em. There was a one month period that I could not get one freeking seed to germinate out of like 50 seeds. I wanted a back-up to my AMS because of the problems very early on.
I am changing the curtains to fishing wire on hooks with clips then hang the panda film from the floor to the top of the HPS light. This should allow better ventilation.
Anyway, you stuff looks great.
Grow on!