Should be fine. I personally use a thick piece of cardboard cut to fit the top of the screen. Then I cut a circle that is 1" bigger than the dome for the CHE and that's all I use. Gives plenty of air. Of course my carboard/tinfoil top isn't airtight either. The plexi top should be ok. If you are worried though, you can remove the cover on the door or drill a few holes in the plexi. They really don't need a huge air hole. Look at all the PVC cages, they usually just have a few slits for air holes and they work fine.