Hi Erwin, Try the truss-rod first. A very slight adjustment makes a big difference. If that doesn't get the action where you'd like it, send me your address and I'll send you some neck shims at the end of the month when I get back from NAMM. These are a tapered full contact shim that slips into the neck pocket.

Erwin I think the TR adjustment will get you where you need to be. Tighten it about 1/8 of a turn. Resist the urge to go more. If there's still too much relief in about 36 hrs tighten it a little more. I find DW TR's do most of what they're going to do immediately. I did this to my ABII-5 fretted and it worked great. If after doing this you find that the low notes are wanting to almost pull sharp, it's the neck PU pulling on the string now that your action is lower. Screw the neck PU in 1/4 turn on both screws.