Rpm range?

[Chamberpains]

Im curious if instead of looking at the RPM's for a "sweet spot" for fuel mileage. I've looked at it as don't take it over 10 psi boost with a 15-20 psi max. That way if 15 psi won't get you over the hill drop a gear and repeat till your up and over. But I've also been trying to see how it feels to watch the TPS position, sort of like Rawze says he keeps his foot at no more than 1/3 throttle which should equate to 33 TPS out the 100. But I just started this monitoring and finding it very hard to keep TPS that low without rapidly downshifting and losing all speed to a ridiculously slow speed in every climb. I find never exceeding 70 TPS with a fading throttle pedal (gradually letting up on the pedal) to keep it under my goal 15-20 psi boost at the same time seems to get me up and over most hills without literally crawling at 5mph over every hill.
The way I look at it if you gear yourself so that the engine load never goes above say 50% or less then it shouldnt matter how steep or long the hill is or how heavy the load, your getting maximum fuel mileage for whatever codition your faced with. The engine doesn't know its on a hill it just knows its being requested to work and how much is asked of it dictates how much fuel it needs.

The less you demand from the engine the less fuel it takes to get the job done.

Any thoughts or problems looking at it this way?

I guess I should add that I am a step deck flatbed operation pulling anything and everything anywhere at any time. Except California Canada and Mexico. And weight never exceeding 84000 pounds with a 10 speed 3.55 rears