[Big Dave]

I've done some of the stuff you describe.

I general make you drive ratio as low as you can. I have 3.08 rear gears with a 0.8:1 Gear Vendor overdrive.

I lowered my 4x2 F-350 4" in front and 6" in the rear.

Both work.

Your truck presents an unusual opportunity. Having been recently whanged, you could rebuild your bed to taper in (in the plan view) about 5 degrees on each side. You'd have to shorten your tailgate and redo the side sheet metal but it would result in a true bullet-tail

Having overdone the taper I can tell you to slat your cap (elevations view down by no more than twelve degrees. To make the layout easy, use a 1-in-5.5 taper and chop it off at the back.

The distance you drive justifies almost anything.