Putting it all together

This went far more easily than I had feared.

Final alignment. I tapped the neck as far down into the dovetail oint as it would go, and noted whether the neck and body were aligned straight. As it turned out, both were right on the money. There was a little bit of play in the upper end of the joint, so I glued a piece of mahogany veneer to one side of the neck joint and filed most of it off until I had a tap fit all the way down.

Final fitting. You can see the veneer piece I added on the left side of the neck joint, which was then filed down. 

To get a perfect fit between the part of the neck that rests on the top of the body, I reinforced a bit of carbon paper and slid it through the tightened joint repeatedly to find high spots, which I snicked away with a sharp 1/2" chisel.

A high spot from the carbon paper. This was an early round of fitting - eventually most of the surface area was fairly evenly covered with carbon spots, after about the fifteenth iteration of slipping in the carbon paper and snicking off the high spots.

Getting ready for the big moment.

Glueup! 

Once the necks were in place, I leveled, dressed and polished the frets. I was pleased to see a really straight neck on both guitars, needling very little removal of metal from the fret crowns.

Fitting the nuts. I removed the veneer and binding right down to the maple.

To get the best fit, I dirtied up the bottom of the nut with soft lead from a carpenter's pencil, then wiggled it back and forth in its slot, again snicking off the high spots, this time with an 1/8" chisel.

Finished nut fit. Pretty good. Left a lot of bone there for stringing later.

In the white, ready for finishing.