Looks like a great start.....how many Herms are going to be in there....is it for night and cooler season for indoors?
Is it on wheels/casters? If no you may want to rinse pull it away from the walls enough to be able to scootch in and around it for when you clean or if you have an issue where you need to get to that side...
Apology...I am using my dumb smart phone and it will change or add words when it feels like it.....please totally disregard the word "rinse"....my phone was being a wiseguy....
Don't forget, once you add 4 or 5 inches of substrate, the sides won't be near that high...and he just may be able to scale them. One way to foil him is to put a lip on it.
what mill thickness is that poly sheeting? at first i was going to use black visqueen but my Russians claws would rip right through the liner. looks nice and big, but man you better hope they dont really try to escape, all it would take is for one to climb on the back of the other and they are out on bail!