Neck screws for jazz type bass

[Randy W Lopez]

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.