I think I fall into this Gary's camp for the most part. The only exception on my part is more alchemy than science. I will sometimes vat the dregs of bottom to middle shelf selections just to see what happens. The last go round included four very low end bottles we hadn't touched literally for years - Echo Spring, Colonel's Pride, Old 1889 and Old Crow. Oddly, the vatting, while still very young and somewhat harsh tasting, was certainly better than any individual component. But that was blind mixing, not scientific calculation.
I don't mix bourbons. It's not that I consider it sacrilegious or anything, I just don't feel the need or see the point. Put simply, I don't ever remember going to my bar with an 'itch' that a prefabricated bourbon couldn't 'scratch'.