Is it an actual Bomar, or a Bomar type sight. The first place I would call would be the manufacturer of the sight. They will have all the specs on dovetail angle and depth of cut.
I had a similar issue recently. I just built a compact 45, and wanted to mill the slide to accept Kimber Meprolite tritium sights. As I was buying the sights from Brownells, I called them first. Their tech guys are good and might be able to help you with a "Bomar" but they didn't have any information on the Kimber sight since its primarily sold for replacement, not new installations. I called Kimber and they were happy to give me information on the dovetail angles and the depth of cut, but couldn't give me any information on the relief cut for the rear sight because that depends on the style slide you have. I finally removed the sight from a Kimber that I have and took all the measurements I needed.
One of the most difficult things is figuring out how long to make the relief cut. you want the back of the sight to sit at the rear edge of the slide, but the back of the slide is angled, so you need to figure out where the rear edge is going to be once you have made the relief cut to the desired depth.
