Re: Guitar Brass inserts for control cavity screws.
Well, the thing about Velcro is that it doesn't really lay flat. You can't get a tight seal like magnets or screws can.
I think magnets for the truss rod cover is a good idea, too.
Re: Guitar Brass inserts for control cavity screws.
Grover Jackson used inserts and machine screws as well as metal covers on the USA Chicago custom Washburn guitars from the 1990's. Also use inserts and machine screws for the direct mount pickups. Great system as no stripped screws ever!