Yeah, that site was one of the first I had checked out; even they list 17's and 18's when they simply will not fit in 90%+ of aftermarket cases. If you look at the factory 18's that come on the lower trims even they can hardly fit a business card between the caliper and the barrel, and when you pull the wheel off the barrel is kind of indented where the caliper would sit with the +20 offset.
I've been going through this myself for the past month and a half. (I ordered my first set of wheels a week after I got the truck, they didn't fit, ordered a different set, so on and so forth).
I'm just warning people that a lot of manufacturer's say that 18's will fit, some even list 17's. They will 100% not fit unless the barrel is very flared (which none of the big guys are like fuel, kmc xd, etc). I spoke with TSW on the phone and they have even sent an internal memo letting their employees know.
In any case, was more or less just trying to get what the largest diameter people have gone with their factory air suspension.