I recently had a fretless bass setup up by a guitar tech friend of mine. I've had the neck on a few body's and started getting some movement. He drilled and put dowels in the hole's and reattached with larger hardened steel screws. I plan on starting another project shortly, basically a fretted four with a Allparts maple on maple with pearl block inlay and binding, basically a 75 reissue neck. I already have the complete body. I'm curious as to what other's have used to attach their neck's and as to size and screw material. Holding well? I do plan on going the 4 bolt opposed to the 3. Thanks all.