Nothing much to add.
I finally got sick of hemming and hawing and figured "worst thing that could happen is that I "eff" it up and have to start the neck over <shrug>".
Drew up my measurements right on the neck black, and then use a straight piece of MDF as a guide for my flush trim router bit. I could go the full depth, so I went halfway through the neck blank, and then used this initial rout as the 'guide' for doing the bottom half. Standard procedure, I think... not necessarily for necks, but for flush-trim routing in general.
I already had a headstock 'template' I had made with MDF, but I didn't think it was very well done, so I cleaned up one side and then used my old "flip and reverse" trick to make it symmetrical, using a hole that will later become a tuning peg hole as one anchor, and a centre hole that ends up somewhere in the truss rod area.
Trouble? Well... the truss rod channel was already routed, so I had nowhere for the second screw to go! I could have just used another tuning peg hole, but instead what I did is wedge some maple into the truss rod, and drill into that. Once the routing was done, I simply removed the maple I had wedged in there.
There were a few hairy moments while routing:
1. The clamps kept getting in the way. At one point in time I had little choice but to unclamp and then reclamp. The end result is that my rout wasn't perfectly straight after all. The teeny deviation is something that can easily be sanded out, though. I went almost 2 full millimetres wider than I needed to in order to get some wiggle room, and that bump you see near the headstock was a casualty but is actually even further out from my line (like 4mm) so I haven't screwed anything up that can't be fixed.
2. The router bit kept getting hot. That meant that I was burning a lot. A LOT. Not smoking-hot, but enough that I'd have to do a lot of sanding if I wanted a natural finish. Luckily I already know that I'm not doing a natural finish, so I didn't mind.
3. In the headstock shape, the bits that come to a point were getting a bit... dodgy. I was scared of getting a bit chip out, so I went extra slow and extra shallow, which partially contributed to the burning. BUT, in the end it seemed to work.
If you look carefully at the picture, the shape of the headstock right at the end doesn't seem to be symmetrical in the photo... in fact, it may be a bit off in real life, too, and I just didn't notice until "developing" the picture-- I'll fix it with a piece of round wood and some sandpaper if that turns out to be the case.
Next step:
thicknessing the headstock. In many ways, it could of and should have been done first-- before gluing the scarf joint, actually. But since I screwed up and DIDN'T do so, I'll have to devise a way to do it now.