Wheel openings: to my eye, the trick is to make them look unaltered and related so to speak to the front openings.
My old SS Duster and the current project both retain the upper flared contour, but are cut starting about 2-3" below the center body line. Bottom of cut is to/flush ft of the tub. The racecar is also cut at the rear, and with minitubs & 3" relocation, 13x31s on 15x12 4BS fits fine, 14x32s would be a bit tight. Narrowed D60.
Project is cut almost the same in front, none at rear, measures like it should just accept a 295/65R15 on a 15x10 (ideally 5.0BS) with stock tubs & 3/4" relocation. Stock 8.75.
Both have upper lip rolled up, excess flange cut - take a good look at that area - racecar being thinner than project because I didn't want to cut the wheelhouse itself. Its flange is about 1/2" because of the stock wheelhouse contour. Racecar eliminated that and filler welded in.
Contours at front/inside of tub are another interference point at around 31/32" tire.
Pie-slice allows retaining the stock flange, a tight cut affect clearance only about 3/16".