Thanks, I will research the numerous product suggestions offered above.
Matt, your experience offers validation to some of my thoughts on the actual engineering of how I plan to design the stock drop of the comb. Consideration that always come into play when planning a custom rifle.
John, these RD sights are advertised as infinite eye relief and my testing so far has shown that whether they are close or at arms length acquisition of the dot seems to be the same. However having said that I don't think I will be able to truly know until I take the plunge and mount one on my project.
The Aimpoint 34L system will not be an option as it appears to require more than a single point of mounting to typical express rear sight dovetail. At least that is the current design.