I sanded off the old Teak/Holly plywood which was only 1/8" thick. I glued the ply to a 3/8" sheet of marine plywood.
Once the vermiculite was removed, I cut templates out of cardboard then made plywood stretchers to support my new floor.
These stretchers were cut out of 3/8" marine plywood and fiber-glassed in place.
The new floor fit like a glove and I think it looks pretty good with it's new teak oil finish. You can see that I started filling the sump with resin. This is a slow process of poring in a little and letting it harden (and cool) then adding a little more.
I weighed all of the Vermiculite that was removed and it was just under 200#. This doesn't include the water that it was holding. I can assume that the boat is much dryer and lighter now although I added 5 gallons of resin.