Well, today I measured out the line for 10, 11 and 12 inch water width and practiced positioning the piece of glass. It fit best at 11 inch, at 12 the left side was buoyed by the silicon edge and at 10 inch the right side was buoyed. Although after sitting for a bit the silicon at 11inch was indented, it didn't give any bounce to the glass so I think its safe to stick it there.
I scrubbed the tank today with a microfiber cleaning block/sponge, and flushed it with water. I'll clean again tmr and flush some more and then let it dry before rechecking the 11 inch vertical line, checking its still good to use on the silicon, and then siliconing it in! Pretty exciting! I'm still blown away I'm actually at this point of doing and not still dreaming!
I will sandpaper lightly the silicon before I start the fixing. Need to find a way to support the glass so the silicon can set without any pull. Although the piece of glass fits snug and probably won't move, I just want to be sure

Sent from my R5 using Tapatalk