Sure Ray,
Being that I use stock removal it may be a bit different if you forge in your taper.
I start by drilling the tang while it is still flat, that way the holes are perpendicular to the tang (90 degrees).
After some input on another forum, I went ahead and built a holding fixture for drilling the scales.
Basically it clamps down on the flat ricasso area and holds the knife at a perfect 90.
Then with a couple small drops of super glue and a couple clamps I put the scale on one side and drill it, flip the blade and repeat the process.
Voila!! Holes that are all magically aligned perfectly!!
This jig will also make drilling odd shaped material like stag and horn, a piece of cake.
I hope that makes sense, this is my first tapered tang, so I am no expert.