Just achieved my current one way personal best from work to home.
50mph max, load based cruising, mirrors folded in, engine deceleration whenever possible neutral coasting up to stop lights as well, AC off, windows up, 93oct, 100% full tank of fuel.
So next on list is putting the grill block back on. 50% to start then I'll go either 100% or 75%.
After that it'll be the belly pan and then the rest of the bottom.
I like what you did for your belly pan. Looks simple and I could carry that idea almost all the way to the rear of Tahoe.