I found this this website, haven't bought anything yet but it seems reasonable. https://myfireplaceproducts.com/ca_en/
Just a note. Glass creates a lot of static and in the dry winter you can expect a lot of shocks. A wire brush in the belt grounded to the frame will alleviate the issue.
I also don’t find the verticals edges of my glass to be straight. I have to compensate for it especially on the plunges. So why I’m saying this is, mine came already attached, so if you buy one for your steel platen check it’s square before sticking it on with JB Weld or whatever. It won’t come off in one piece if you don’t.