Haven't had Ecco recore anything yet but Nick whipped up a 5/8-11 Bravo mount for my RPB M11-A1. Between the turn around time and the stellar quality I would not hesitate in the least to let him work on any NFA item I own!
100% ECCO Machine. Nick is a stand up guy. Talk to him on the phone and go over your options.
There is a guy (FFL/SOT) that uses the F1 board, that has made the spiral stack found in MAC suppressors. Typically I think his Forte is High Standards