Rusty,
I shape the tang first, leaving it very slightly oversized. Maybe a few thousandths, but not by much. This allows you to get the holes where you want them, since usually they are a margin from the edge. Then I clamp or glue one scale and drill through the tang and through the scale, placing a temporary pin in that hole. Then drill another on the far end of the handle and put a pin there, then drill the rest. Place the second scale on and do the same procedure. Now you an shape the scales to the tang and pin it up. If you have any questions just holler back. Lin