If you're still up for ideas, and Have neck completed, Clamp the neck about where you want it, finding relative center, using a shim between the fretboard and clamp, and use a straight edge down the sides of the neck, and mark a fine pencil line, then center your bridge at scale length. Trace a line around the the neck heel to show where your neck pocket will be. Remove the neck and clamp, now line up the Trusty stew mac Neck template and stick it down with double sided tape and fire up that router, cutting that neck pocket to the correct depth. 2 3/8" is width of my lines at the bridge, and you want to center that with relative center of the body as well.