
Thanks, it's definitely more than it needs, but it's always better to go overboard and have piece of mind. I should also add that after a viewing panel is installed you need to add bracing on top too.
I used Pond Shield by Pond Armor. It's a two part epoxy that you paint on. It's basically a very thick paint, very easy to use. I used 3 coats but probably could've gotten away with 2. again, better safe than sorry
I'm still contemplating trying a pond liner with an acrylic viewing window using 3M 5200 and SS bolts for my first tank.
Im also leaning towards your approach with pond shield and then siliconing a viewing glass windows in place. Did you fiberglass your seams? I was wondering if I could get away with only screwing and gluing my corner pieces together and just use a few extra coats of pond shield to make up for it. I have zero experience with cloth.