Just to chime in - I'm a big fan of the adjustable neck arrangement, and am using my own approach with everything I build.
Rather than adjusting the angle, though, I prefer to slide or "translate" the neck up and down, while maintaining the angle. This minimizes one common issue with angle adjusters, which is a significant change in tuning during adjustment.
The "vertical" or sliding neck joint approach actually requires minimal or no retuning with small to medium adjustments - it's actually practical enough to do between songs!
Ken Parker's neck joint is a sliding adjustment, not an angle adjuster. He's dialed in the angle carefully so it doesn't go out of tune at all - and it really works!
The sliding system also allows for a bigger active contact surface between neck and body. Most fulcrum-type systems necessarily rely on fairly small points of contact.
Here's an exploded view of the "guts" of my neck joint:
And here's the adjuster access on the finished guitar:
A 1/8" allen key adjusts from super-low to slide-high. This is a "push-pull" system, so it does not rely on string tension for movement in either direction. There's a nice big contact surface on the "rails" of the track, and it moves smooth-as-silk even fully up to pitch.
As for how it compares to a hand-cut dovetail, I'm not going there...this is a very strong and positive joint, and I'm more than pleased with the results.
Cheers!
Martin