[email4eric]

If I may add to the above suggestions...

I spend a fair amount of time making sure I determine exactly where the rest needs to go. I use blue painting tape to mark the two ends where the rest will locate on the guitar.

Once that's been determined, I spend some time "dry" mounting the rest and observing any mismatch between the rest's outer shape and the shape of the lower bout such that I can determine where some shaping of the arm rest should occur.

I sand the arm rest where needed to perfectly match the radius of the guitar. Then apply.

Beside the improvement, I find a little bit of employed craftsmanship adds to my "bonding" with my guitar.

Arm rests will grow on you and I've seen "never-an-arm-rest-for-me" types converted!