A good way to make tests, as mattia pointed out, would be to build a guitar on with interchangeable tops... Then tests would not be so hard to do.
Hell, that could actually be a good idea for sale... Have different tops for different styles of music, with the same guitar
About volume, there's also the perceived volume that can be misleading... With my O', I almost can't hear myself when i'm playing unless I put me head near the top\soundhole...
I suppose that means the sound is less "wasted" on the back and sides of the guitar and projected on the top, at least in theory... And btw, even with the shallow bowl, my guitar is almost as loud as my friend's when strumming, wich has a Jumbo...
Anyways, I think it's good to see great builders like you guys think about the bracing, seeing how most high end builders don't even ask themselves the question and build "good old" X bracing...