The Lesser of 2 evils

[Inknsteel]

I have some polycarb sheets but they have 50+ 1/4" holes drilled out. So the snakes would be exposed to the same air but not direct contact.

That would be sufficient, definitely better than nothing. By using the divider, you are at least giving them each their own space where they won't be battling for the better hides or a single hot spot...