Justin, the holes in the sight mount ears came with small holes drilled in them for locating purposes, I never measured what they were originally. They were small enough to allow drilling and reaming them out to whatever size you need. The pivot screw that came with my sight has an 8x36 threaded end and a lightly larger body. Hope that helps.
The distance between the sight ears is around .213-.215, depending on how true I was holding the calipers.
You asked what the rifle weighs, I forgot to respond to that question earlier. I haven't weighed it yet but will try and remember to do that and post the results. I am certain it will fall under the 13 pound weight limit set for the international matches. I think there are a lot of Alex Henry match rifles shot at those matches. Perhaps Snapper can jump in here and shed some light on the subject when he sees this, he has shot (and won!) internationally.
Here are some photos of the bottom of my rear sight and the spring as seen from above the tang... It was originally flat on the bottom and I filed it to the shape shown. The Soule sight you have likely has a round bottom on it, that would work fine if the spring stop notch is in the proper location.
Curtis