Filling Holes in the boat

[Sean]

I think I will be cutting a few 6" holes in the deck this afternoon so I can mount the T-top and through bolt it down to the hull. (I was just going to use sheet metal screws/5200 but the glass is slitely pulling from the plywood so I am not confident in it holding)

When glassing back over the holes what is the best method to support the floor? The holes will be located under the gass tank and next to the console so there wont be to much if any traffic/direct preassure on them
Do I just keep layering glass and hope for the best?
should I screw wood under the deck and glass over it?
Sorry no pics, I got a call from a buddy that is going to help me do it today, so it is kind of last minute.
You know the schmeel, any help/suggestions is always apreciated.