17" Wheels with KH Disc Brakes

So I stopped by the Motech booth today at Fall Fling and they had a special for 4 wheels for $498. It can either be painted grey or black and be either 7" wide with a 4.25 bs or 8" wide with a 4.5" bs. Anyways, I was wondering if anyone knew what would be a good tire selection if I were to use one of these wheels. I could also get them in an 18" wheel but that just seems like more rotating mass and a lot of empty space inside the wheel due to small rotors and drums.

Essentially I'd like to fit the widest tires under there with the least amount of modification. I'd like to use the Dart as a cruiser for now with a couple days a year running on a track (like Willows or Adams Raceway). I'd eventually like to build it up to be a nice corner carver (big T-bars, Hotchkis suspension, FF parts, etc.).

Right now I'm running a 14" wheel with a 205/70/14 tire. I've got KH up front and 10" discs out back under the 7 1/4. Before I put new wheels on this car, the 7 1/4 will come out for an 8 3/4 I have sitting in my garage. It just needs shock plates, a shorter driveshaft, and a good look over. It is currently a 489 case, open, 2.76:1 rear end with what I believe are 10" drums. It came out of a 70-71 Dart.

The guy at Motech recommended a 215/45/17 up front with a 7" wide wheel and for the back either a 235 series tire for the 7" wide wheel or 255 series for an 8" wide wheel. Can I fit a 225/45 up front? Should I go with the same tire size all the way around or stick with small tires.

If I go for a wheel, it would probably be the black one:


An 18" wheel on their customer's '72 Duster with BBP:


One of the other show cars: