Spud said:
I was just thinking of satin black, but I may skip it. I don't think stain is gonna penetrate the maple well.
Dyes will penetrate maple well, otherwise PRS would be out of business.
Sand, then moist with water to open up the grain.
Warmoth puts a penetrating sealer on their necks (it can be ordered without) but another member had no problem staining the neck despite it.
The end result will not be a uniformly black color, and some grain lines may not take the dye well.
On plain maple the end result could be blotchy but it should be fine with a highly concentrated dye and several passes.
You may also have a hard time keeping a clear line between the front and sides of the headstock though.
If you are trying to approximate the look of a solid painted headstock you will likely be disappointed.