7.25 drum to drum measurement

Sorry I got to this so late. You’re right, that measurement is crucial. I managed to make it to shop and up on ramp to measure. We measured 3 times and got 55 3/8” . My shop are excellent at chassis set-up - we had a long chat and agreed we’d go with the drum to drum measurement we had and would look at offsets and spacing once we have it on (which will be mid to late January). All being well we’ll be golden!
might get a bit interesting....for a wide rim in front, to fit a decent tire, you're going to need probably 19-30mm positive offset with an 8" rim. (5 1/4-5 5/8" backspace). with that narrow of a tire, you're probably going to need 0 offset to -15mm offset to maximize your tire/wheel size. something more like 58-59" wide if you wanted to keep the same offset front to rear probably would have worked better. at least that's what the math tells me after I measured my duster.