Does anyone have any suggestions as to what brand of strap lock I should buy? Or what's good from among these three: Dunlop Original StrapLok System, Dunlop Dual-Design StrapLoks, and Fender Strap Locks. And how difficult is it to install these things? I'm not looking to drill a bunch of holes in my bass. Also, I've read something about having to buy special buttons for the Dunlop systems. What's up with that? Are they included? Thanks in advance.