I am currently working on my second 3 piece longbow. I drilled the holes tonight sans a drilling jig. I elected to drill the index pins through both the limbs and riser for simplicity sake, the limbs will now need an overlay but they are decrative, right?!
I think that 3 pc bows are pretty simple so long as you really secure the limb/riser while you are drilling it. Also, after the limb bolts are drilled, tapped, and inserts glued in, I use a length of weighted red fishing line to line up the limb tips with the center of the riser prior to drilling the index pins. This process is almost fool proof but I really take my time and measure it a BUNCH of times prior to drilling.
I think that after I make a couple one piece bows I am going to have to try one of those fiberglass sleeves similar to BW bows. That is really slick and I can't wait!