First off, Thank you so much for your opinions and ideas!! I really am grateful for you guys helping me brainstorm some ideas for a decent lid!!!!
I haven't considered removing the eurobrace as I don't really find it an encoumberance. Plus like you said, I built some ventilation system that I stuck right under it so it's actually hidden and made it easy to just glue it under there. Basically some 1in abs pipe in which I pierced holes which computer fans are pushing air through, keeps glass condensation free and creates an airflow which improve air quality in the tank.
I thought about making a wood canopy at first but then I thought about all the CRAZY heat that will pull from the electronic in there (2x 48in finnex planted+ along with a UV basking spot, a 60w basking spot, and 4x 48in current-usa freshwater+ strips!), plus I need air exchange (screen mesh) so not such a good idea. Also, I guess you need better access to the vivarium than an aquarium? I'll need to put both my arms in there at some point to do cleaning, feeding, pruning etc, and that without the gecko escaping!
If I leave the eurobracing there, and use it as a wider/stronger ledge to just sit a wood or polycarb crossbracing frame on, do you think that would work? basically swapping the glass for wood/polycarb from my first idea...
I don't know if polycarb would be strong enough tho eh? If it warps just a lil bit because of the weight of the glass lids, geckos will get out. I think wood would be sturdy enough... cheaper and I would actually stain the exterior to make it have the same look as my stand!
Here's another drawing of what I have in mind... that's if I would be making it with wood.
Also, if that is of any interest, here's a link to a blog/journal
I am making about this tank!