Hi Heather,
You will be able to a screen place make a custom frame/front.
The top screen area and bottom glass or plexi area could be all one piece within the custom frame.
I used glass on my 40 conversion. I was worried about the heat emitters w/ plexi. But you could get around that. If glass was used it might also add some rigidity? It would be heavy , though?

I had a glazier drill a hole in the top of my 40gal conversion to pass wires and mist tubing through.
Plus this added a little extra ventilation.

You could seal off the bottom /front w *silicone and a piece of glass, positioning it against the inside of the tank frame. The edges of the glass can be sanded smooth by the glaizer.

Then when you remove the custom front frame ( to feed and clean) , the interior* bottom glass stays in place at all times to hold back the water and false bottom.

The custom frame would sit in the outer lip or the rim of the tank.

Hard to explain.