alexclaber
Commercial User
I have an ebony ramp between the P and J pickups on my Warwick. It's stuck on with double-sided tape and contoured to the body on its back and set up about 2.5-3mm from the bottom of the strings. I find it really helps my technique, stops me digging in too far, acts as a thumbrest when I'm playing the E string and helps with using a shifting thumb (i.e. anchoring on E, A and even D strings depending on what I'm playing). I'm also installing a ramp on my fretless for the same reasons. Neither of these ramps get in the way when slapping, they stop a few inches short of the end of the fingerboard.
Alex
Alex