My plan for new wheels, what do you think?

275’s aren’t supposed to be mounted on anything less than an 8” wide rim. And on an 8” wide rim they’ll touch the springs and the quarters at the same time with the springs in the stock locations. Not only that, but you’d be deforming the tread, which will effect tire wear too. And you won’t have any more tread on the ground.

BFG recommends 7.5 at the least, not 8. I don't think 1/2" is a deal breaker, it's just 1/4" on each sidewall pulled in tighter. I have ran narrower rims with wide tires plenty with no issues. In the perfect world it's great to go by the mfg specs but wide tire on narrow rim makes the tire look fatter & it pulls the sidewall in for narrow wheel wells.