So 4" wide 1/4" thick should be sufficient additional bracing? Mostly I'm doing this for my own piece of mind. I think probably what came with the tank originally is meant to take care of all the structural needs, but what I'm guessing happened (because of all the silicone) is that the original bracing came off at one point and rather than fix it appropriately, the prior owner just globbed a bunch of silicone on to try to hold it in place. Apparently that isn't a long-term solution. Anyhow, once I get it all cleaned up and re-attached, I'll see how exactly it's attached and if it is in fact bracing or if it actually did sit on the top of the glass like it sort of appears at this point. That will probably be sometime next week. I guess once I find that out, then I'll make a final decision on the additional bracing that I want to add.
next question is - how do I measure so I get an exact fit with the incoming glass? I've never done this before and I'm not confident that I can do it now. If it is too snug, I'm guessing I won't be able to get it in and siliconed? Also, do I just silicone the edge of the brace to the glass, or do I silicone it top and bottom of the brace if that makes any sense... is there a video how-to for this somewhere??