After cutting to the line I put the neck on (unbolted) just to make sure the new shape felt right - it didn't, the angle at the lower side was too square to the line of the neck, so that's going to be sorted later today.
One thing I did do was mask everything apart from the cavities so they could get a good few coats of a copper-loaded "paint" that I've used at work for EMC screening. I'm now pondering if on whether to leave the copper-colour or go with my first thought of having them black. I suppose if I don't paint them I can see what it looks like against the finish and paint if I don't like the appearance, but if I paint them now I won't be able to go back...... I think I'll leave them as they are until the finish is on.
I'll post a couple of pictures later on today.