Congratulations! Building your first cage can be challenging but sooo rewarding once completed. The 2nd one's easier, even if you make it different from the first one. Kudos for takin' the plunge.
I think you would get more efficient heating if you were to cover the heat rope cut-out with a piece of 1/2" or 3/4" foil-faced sheathing - like the blue foam insulation board covered with aluminum foil. For about $15 for a 4 x 8 sheet I'd probably cover the whole bottom with it. You could also use Reflectix but it's more expensive and for that application I think the foil-faced sheathing would be best, both energy & cost wise.
The glass is fine, as far as snakes goes. Us humans are the biggest concern with the type of glass used, which is why some people go with the expensive laminated glass. If something falls against laminated glass it holds together better than the other types.
I think I used laminated in the sliding glass door cage I built, which was my first one in the series of stackable cages I was building, but I switched to 1/8" plexiglass (in wood frames) on the 2nd cage with 2 drop-down doors. You're right about the cost of laminated glass; I think I paid about $130 for the glass shop to install aluminum track, laminated glass & rollers.
For relatively small openings like my cages & yours (aprox. 12 - 14 inches x 36 - 48 inches), there isn't a concern about snakes being able to push through them. It would take too much pressure in a specific point (center of the window) and I've yet to see a snake put that kind of pressure on areas that are "in the open," so to speak. I've seen 'em push in corners of the cage or even corners of doors, but never in the center of a door (glass pane).
What did you seal the wood on the inside of the cage with?
Again, congatulations!
HH
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Due to political correctness run amuck,
this ol' hillbilly is now referred to as an:
Appalachian American

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