The only difference between the 760 and the 7600 mounts is that the 7600 mounts uses a larger screw then the 760.
I doubt if you are going to easily find some of those scope mounts that you have described - unless you do a internet search.
If you did one and could not find the mount that you were looking for, the Kwik Site mount company still makes mounts for the 760 and 7600 rifles.
The basic platform for all those rifles are the same.
You could take it to a competent gunsmith and have them drill out the holes and tap them for the larger screws for the 7600 mounts and have the mounts lapped so they are aligned properly.
I would take off the mounts you presently have, if you have scope mounts and replace them temporarily with the Kwik Sites before having them installed and check the alignment with a old broom stick or a piece of wood dowel to make sure that they line up before having the action drilled and tapped for the larger screws.
The new screws should already have pink or blue Loctite applied to the screws. If not - then you should use Loctite small screw adhesive. along with a Locquitic primer to hold them in place properly.
And - they can be shimmed if there is any severe alignment problems.
In my travels I have seen everything including a old 7 UP can piece of aluminum used as a shim under the site.
How ever - proper shim stock always works best - hence the proper way to have those mounts installed is by a competent gunsmith.
Make sure to have the gunsmith take the gun completely apart and clean everything and lube it once the holes are drilled and tapped and assemble it with the proper lubrication.
That will ensure that your firearm will last another lifetime or two with no issues, as opposed to having debris inside of the firearms which might prematurely wear or damage your rifle.