Don,
I've always followed my Dad's recipe for consistancy.It seems to work very well as LilDemon can attest and verify.
My Dad has always run his cars on the very rich side.His theory has always been a lean car will show bigger variations that a rich car. He also dialed back the timing. Of course this meant he wasn't squeezing every last HP out of the combo.But it insured he would be consistant and the car would run cooler. He must have been on to something... He won over 400 rounds of bracket racing and was a 3 time Goodguys Hot Rod Champion.All in the span of 5 years running a limited schedule from the cool of winter to the heat of summer his dial did not vary more than .15
I applied the same theory to my Dart....went lots of rounds. But the best example was witnessed by Bill (LilDemon),My car was stored in my trailer for a whole year...March Meet to March Meet. I rolled it out with a 10.77 on the window,aired up the tires,threw in fresh fuel. Then went out and went 10.771 on the first pass.
We also clean our air bleeds with WD-40 after every 3 passes....you would be suprised how semi-clogged air bleeds can affect performance.

It just takes time to dial in your package.....make minor tweaks to your program or tune up.