Compression "way above 70" (mechanics words) at all 12
points...

You have a 12 cylinder engine?

Nope! Pressure checked at DTC, BDC & mid travel of piston in
each of 4 cyls.. Total 12 locations..

Hope I have the terminology right, new to me....

Sorry, no Merlin here...

snip

Tach checks show 2350 RPM static when new, still shows 2350
static on the TO run...

On the T/O run is not "static".

Good point, but holding on the brakes (short field procedure) ,
running to full RPM and then releasing...

Check RPM max before the roll...

Close enough?

Dave