I traveled over to south western VT some years ago, to watch a spline jointed frame going up.
There are some pictures of it in my galleryhttp://www.forestryforum.com/gallery/thumbnails.php?album=365
It was one of the first spline jointed frames I had seen being assembled. I watched the timber framer put the drill in the mortise hole and drill out the spline after the frame was standing. (Picture #8) Then he put a crow bar into the spline mortise and slid it over a little amount and then bored the other peg hole on the other side of the post through the spline. Then he slid the spline piece back, just a little bit. Then he drove in the two pegs, drawing the two tie beams together to the post.
As this was all done up in the air I didn't get to see exactly how much it was draw bored. And it was a white pine frame with oak splines.
I know this probably doesn't help you much, but that was an interesting method of draw boring a spline in place with the frame standing. After it was all done they released the truck strap going around the frame from outside post to outside post.