step up from pro sema rims.. offset wise

so i have a set of sema rims on my pro,, my question for the offset and backspacing experts is,, going to an 8 in wide rim, and moving 1/2 out and 1/2 inwards... seeing as the sema rims is 7 in wide...keeping the same in and out , 8 in. rim instead of 7 in wide rim... its confusing when considering a aftermarket rim, want to order the right specs,, thanks

 

The exact specs for what you want to do is an 8-inch wide wheel with a +4mm offset. I'm not sure any wheel manufactures offer wheels in these dimensions though. 17x8 with 0 offset (assuming you're looking to stay 17-inch) is pretty common and will sit pretty close to what you're looking for.

Here's a wheel visualizer/calculator that you may find useful. 17x8 6-139.7 Wheel Options | Discount Tire Direct