well a while back i asked about that gun and a really nice guy made a mod just because i asked about it. it was done by "akdavis" who did something with the clip distance so your nose isnt pressed against it, there was a minor issue with the tub view so i think it needed a little more refining. i never understood what values he was changing but even though it wasnt perfect i was happy with what he did at the time because the gun was usable finally.
maybe if you get together with him and putting your mod and his together would get a thinner gunsight from your version and fine tune the proper view distance with his.
this is his mod link
http://files.filefront.com/20mm+sing.../fileinfo.html
and this is the thread about it
http://www.subsim.com/radioroom/showthread.php?t=137027