The weight will be fine until you drop it! My first canopy for a 150 long (6x2x21) was made from 3/4" plywood and reinforced using 2" aluminum angle. I realized even before I put it on the it was way too heavy, but at least my 4' Undulated Moray never escaped again!!!. I'm guessing that it was north of #100. Every time I lifted the front up I was worried about it breaking my arm (or neck) if it fell.
When I made the canopy for my current 120DT, I used 3/4 cherry for the frame and 1/4" cherry ply for the panels. It is a much more reasonable #20 or so and is suspended from the wall in any case.