Dan,
I recently worked on my teak and holly soles on my 1988, so I can answer most of your questions. The panels are almost exactly 1/2” thick. The panels are screwed down around the edges with small (size 6 ??) screws. You may find that the screw heads might have submerged into the wood, depending on the skill level of the previous owner, and might be difficult to see. As you loosen each board, gently lift the edges and you’ll be able to tell where any remaining “hidden” screws might be. When you reinstall, you might consider small washers beneath the screw heads to keep them closer to the top of the wood.
The boards over the bilge are two 1/2 panels glued back to back making them about 1” thick.
Each panel sits in a fiberglass recessed pan that is the same depth as the thickness of the wood, so if you remove the wood panels, you can still safely walk around the boat.
I don’t have a measurement for how deep the bilge is, but refer to the attached photo – I’d guess about 10” or so? Maybe someone else can answer that one. Note - in that photo you can see one of the screw heads on the corner of the panel beneath the table. They are pretty small and easy to miss.
Free advice (worth every penny) – be really careful refinishing the sole panels. The veneer is VERY thin. I’ve attached a photo of mine, which were aggressively sanded by previous owners, and you can see how the holly is missing in a number of places. For now, I went ahead and very gently removed the existing finish and revarnished to do what I could to improve and protect, but I’ll eventually need to replace the main long panel and probably the galley.
Take the time to seal the undersides of the panels too. Water, dirt, sand gets beneath them and damages them. I’ve started periodically pulling up the most heavily trafficked panels and vacuuming the pan beneath them. You’d be amazed at how much sand collects under there.
If you have dents in the wood from dropped utensils, etc. , you can “undent” them to a large extent by placing a (nearly dry) damp towel over it and use a clothes iron placed on the towel to drive steam into the wood. Don’t overdo it or you can delaminate the veneer or scorch the wood. Sneak up on it a little at a time, and you’ll be surprised at how the wood fibers will swell up and fill back in.
Good luck on your projects!
Tom