Well, i'm worried about introducing what i would call hysteresis resistance (?) to describe an over-inflated tire not conforming to the rugosities in the pavement, and introducing additional drag.

It may be tough to find the right pressure. Its telling that Continental's 'sweet spot' recommendations are between 22-36 PSI on the tires.

I need to do some torus volume calculations to determine what, exactly the differences in volume are.

Let me go out to the garage with a tape measure, clipboard and a calculator and i'll post some numbers.

then, a morning ride at 25f/30r and see how that feels. I know, those tire pressures sound absurdly low.