I know you're aware I'm a bit of a "wheel hound" so I have spent entirely too much time looking at wheels and considering my wheel and tire options. Like, WAY too much time.
If you want to run square with big wheels, you can go up to 18x10 and a 285/35/18 with work on the front fenders (rolling, flaring, brace extensions) and a 1/2" spring offset in the rear. With that set up you'd be best off with a 65-67 or 68-70 B rear and your 18x10's with offsets in the +30 to +40 range with the wiggle room being what disk brakes you're running and maybe a small spacer.
After I did the "reverse tub" on my Duster and started looking at 18x10.5 up to 18x12" wheels I figured out pretty quick that 18x10 is the break over, from 18x10 up there starts being a lot of lower offset
