CurtO:
You'd have to speak to him directly, but if there is anybody who would properly conduct and experiment, it would be Al Carruth. He has performed a lot of different experiments, some of which he has written of on the Acoustic Guitar Central Gear forum, probably some that he has not written about.
I do know that at one time, he actually built two guitars, with woods as closely matched as he could get them, with the only difference being that one guitar used a standard X bracing system, the other one used a Double X bracing system (like Gibson tried at one time). While the Double X has long been discredited as being to heavy and stiff, leading to a lifeless sound, in his case, he found that people very much preferred the sound of the Double X braced guitar. In his experiments, at one of the shows, he did the experiment with the player being unaware of which guitar they were playing, and there was a wide variety of people who tried out the guitars, from fingerpickers and flatpickers, beginners, intermediates, and even a couple of nationally recognized pros, as well as other handbuilders. He was just proving to himself that there was nothing inhereintly wrong with the Double X bracing system, it was more the way that the original Gibsons were made (ie. execution vs. design). He has also done a lot of work with glitter patterns, and trying to equate what is being heard with measurements.
I have never even met the guy, but his postings sure are very enlightening, and I always end up learning something.
Kostas