The neck in my OM kit from John Hall came from Hannalei-Moon. It's a beautiful mahogany neck and I highly recommend Chris.
I wanted a traditional Martin shaped headstock......even though this neck has a smilee volute. I made a template using UHMW but it sure is difficult to measure and mark the lines perfectly.......so the template is less than perfect. Here is a shot of the template (I may later add tuner holes):
I used the template to mark trim lines on the back of my headstock and was able to use the table saw to make the trim cuts. This is intimidating since the taper of the headstock has the blade cutting toward the neck. In the end I trimmed it close then sanded the last 30 thousandths or so as the fence on my table saw isn't that great to make a fine adjustment.
So are you curious what a Martin headstock looks like with a smilee volute??? Here are pictures: