thanks everyone for your sugestions and ideas, I contacted Shawn on etsy, but he seemed to think shipping a finder to the U.K would cost twice what the finder cost!, the ttartisan finders look like the way to go, I've got a 90mm schneider super angulon i'm going to use for the build, looking on the net the 90 on 6x17 gives a viewing angle of 20-22 degrees (varies from website to website) so I'm going to try a 21 degree ttartisan viewer and hopefully can mask it down to give a good aproximation of the 6x17 field of view