Connect it to the gas pedal inside the car and make it connect to an adjustable knob on a threaded rod so you can fine tune the load position . . . makes me want to go out and build one right now! My gas pedal is way too light and I have to hold my foot off the pedal all the time.
Personally, I don't know about the throttle versus rpm debate, but it seems that darin has made the switch from minimal throttle pressure to moderate with no hit in gas mileage, and as mira has said, the real issue is what you do to lose that speed once you have gained it, not so much how you get there. I generally practice low throttle because it's easier for me to do consistently, but I often do the moderate throttle thing when the benefits are obvious.