Those Running 3.73 And a TF w/ LockUp.. What's your highway Driving Like?

I've had 3.55s in my Duster with a non-lockup 904 for the past year and a half, acceleration is excellent but the cruising RPMs got on my nerves enough that I'm swapping the 2.94 3rd-member back in. Freeway speed limit here is 70 mph between cities and most traffic cruises at 75-80, 3200+ RPM at those speeds gets old pretty quickly. It would be tolerable at 60 mph but then I'd be getting passed by every semi-truck and minivan on the road. Gas mileage sucks too, iirc it's around 13 MPG with the 3.55s. I've gotten 17-18 with the 2.94s cruising on the freeway.
Right on.. Nothing like real world advice!