Heater location / Cabin pan profile?

I am trying to think of a good install location for a Webasto (Evo 40) heater. I'm thinking on the floor aft of the engine to the port of centerline, with the 90mm output duct in the small wall under the starboard quarter berth between the stairs and the ice box. I have a used 90 degree aluminum mount from a previous install that will mount the heater to a floor or wall.

It looks like the floor aft of the engine and stuffing box is not the hull itself but a pan insert. Does anyone know how much clearance I have underneath this for screws to poke through? And is it glassed to the hull (i.e. no clearance) in the middle but tapering up (i.e. with increasing clearance) as it goes laterally toward the quarter berths? I guess a cross section would be helpful.

Thanks!

Mine is not a pan, it is the hull itself.

I mounted a diesel heater to the wood bulkhead on the port side in that space, rather than to the floor. The air outlet comes out as you described but under the port quarter berth aft of the galley.

Turns out mine has a pan insert with varying clearance but plenty to drill through carefully without hitting the hull. Installation was easy on the insert with an aluminum bracket. Outlet duct is below starboard quarterberth.

I installed mine to the bulkhead behind the engine. Works really well