I have a 11 5.0 f150. I'm mod-Ing it into a sport truck. Lowered etc. I'm having a hard time finding wheels that I like. How possible is it to get like 1.5in 6lug to 5 lug spacers and use mustang amr 18x10 wheels? They have a 7.2 back space and a +45mm off set. I'm confused on how to measure bs and offset to determine how much the wheels will stick out. I want them to be flush with the fender, no stick out. Any help or opinions will be greatly approcated. Would do like a 295/50/18 tire. It's also a 4x4 that will be lowered 2front and 4 rear

 

If you are looking into the sport truck venue side of things you'll ditch the 18" wheels and look more to the 22" as that will give you a lower profile tire and wider tread. Or at least the 20" if 22's are not your thing.
These are the 22" 2015 Expedition wheels. They would look sweet on the F150.

 

I had to look for it but here is a neat tool to help you compare BS and Offset.
https://www.rimsntires.com/specspro.jsp

 

I'm running 22x9.5 kmc slides, 6.75 back spacing with a +38 offset. With the factory flares the wheels and tires are sitting just inside, just like the factory 22s did. I wrapped up installing my lowering kit last night, after I get it back from alignment I'll wash it and try to get some decent pictures. I went with the 2/3 belltech 978sp kit. These are pictures at stock height. Custom offsets is a good website to look at different wheel and tire combinations.