I'm going to hot glue all the way up and down the divider and make sure there's less than 1/4" or even less between the top of the screen and the divider, it should be fine with a cut up plastic hanger hot glued' in the middle. both t's are 3.5"+, I'm actually going to do this right now, i'll post pics when I'm done!The problem you will face is making sure there is absolutely NO gaps at all they are escape artists - several threads I have read tell the same storey " no gap, how did it get to the other side?"
Be carefull, maybe try something like a roach on each side and see if one can get to the other, if a roach(climbing roach BTW) can't get over then maybe a T can't either. Keep us up to date.
that's a lot of dirt! i'll have to go buy more tomorrow, thanks for the adviceFor a terrestrial you should fill it to about 6" from the top of the cage. The screen should be replaced with plexiglass (w/ holes or vents) so your T doesnt get its claws stuck in it.
Edit: You should move the cages away from the window to keep them warmer.