Ozzy
Albertporter, I own the Eggleston Andra 2's not the Focals.
Sorry, occupied with holiday guests and not paying attention.
My offer still stands if I get blessing from Stillpoints. I think Ultra 5 is solid stainless steel and no harm would come by drilling and threading.
I don't like the adaptors for my application, the difference between 14MM and 1/4-20 is too great. For your 3/8"-16, Tbg (Norm) is probably correct and you would retain resale value if you needed to move them later.