I cant think of a better tool for the job. Very slow process. You should plan to go through about 18-24 cutoff wheels before youre finished.

Tool of choice - Dremel with right angle adaptor

You can see the void between the hull interior and the false bilge.
This photo from inside the forward end of the bilge looking aft, was taken after removing most of the false bilge floor and the rotted plywood sheet.

Closeup inside H34 bilge during surgery

I found several areas around the sides where the glass they draped into the pan/bilge did not even contact the hull walls inside the hull bilge. No problem for water to settle in the bilge void beneath the floor.

I have several more photos (hi-res options too), and will continue to document the process for those of you who want to repair this undocumented feature of the H-34

Cheers!

Floor out, some grinding of walls done