I talked to Lee Shaver a couple times about their Soule before deciding on the Smith Enterprises ladder. He has two methods of mounting it. First is just aligning it on the stock and screwing it down with wood screws. The other method (more expensive) is to inlet the stock in the shape of the sight, and install a "False Tang" for it to screw to with normal machine screws. They do NOT attach this false tang to the frame. It is glued into the bottom of the inletted stock and the screws are threaded into it. In the end, I decided that the expense was too much for a sight that in the first method was simply screwed to the stock and in the second method essentially glued via the false tang.
Ian
P.S. Don't hold your breath waiting for a reply to an e-mail, he's swamped with them. Your best bet for talking to him is to call.
P.S. II I'm very pleased with the Smith.