Bruce, with the Whipple set-up, you should NOT see fluctuations enough to cause you so much concern, in my opinion. In other words, you should be able to get a tune in your car and validate it on the dyno to be safe and have the right A/F's.... and that should be it. I know this far that has been elusive for you but maybe it is time to get Torrie to Socal. In fact, we could probably get a whole group of forced-induction GT's together and split the cost to get Torrie here to do tunes. I can rent the dyno for the day. Give it some thought. (We should start another thread, if interested.)
The turbo guys are really the guys with a whole lot more variability as they can easily change their boost levels. In fact, that gauge you see is not merely a gauge but an electronic boost controller that lets you set different boost levels from the cockpit of the car. As I said before, you whipple should be a "tune it and forget it" endeavor - with no need to monitor/worry about boost and A/fs.