MIMF

Instead of the popsicle brace, I’ve been filling the space between the upper brace and the block with a piece of spruce with the grain angle running 45 degrees to the top. The fit is tight so that the block can’t migrate into the soundhole. The only good picture I have at the moment is a 12 fret, but the concept is the same on a 14.

Nice.

So what does the PMTE shim do?

Also, If I buy Adi tops, whom do (you) recommend for highest .density tops ( IYO) of course.

The PMTE is a brace that sits on top of the bridge plate under the back of the bridge. Mario said it was a tone enhancer, but I am using it to add resistance to doming behind the bridge, which is the cause of a lot of problems with this old Martin. It is not part of the original design but if someone decides to remove it in the future, they can grab it with a pair of pliers and pop it out.

Ok. Found It It's actually not looking too baaaad. Maybe I can keep the X but the rest( braces) don't look so hot. I'll upload pics in a few days.
Measurements: lower bout: 15.25"
Length: 20.75"

I'm thinking...all need to be replaced...

So, best way to remove? Hot iron on top+, heat gun or just heat gun + some water? It's all hide- glue.

They do look a bit thin. The best way to remove braces is to plane, chisel and scrape them down to the top. Spruce is easy to carve and you can remove them fairly quickly. Carving them off will do no damage to the top, whereas using water and heat will threaten the integrity of the top's center joint, and introduce moisture which could cause some instability in the top. A finger plane is my tool of choice for this job.

What Barry said. The nice thing about hide glue is that new glue will stick to it, so you don't have to worry about getting all the old glue off.