offset shackles (how big a tire)

I have the offset shackles/hangers on my 67 Dart with 245-45-17 tires on 17x7" wheels. My axle was shortened .5" inches, too. There is a ton of room under there. I have ESPO springs, which make it sit slightly higher than stock, but not a ton. I know that I have at least a couple of inches between the tires and spring. I haven't measured the distance between the tires and the wheelwells, but I can stick my fingers in between them on the lip. I really don't know how close it is anywhere else.

You can check out more pictures at http://www.damnimcool.com/cars/convertible if you'd like. I know I could have a much wider tire in there without spring contact, but I'm not sure how close it is to the wheel well further up.

I chose this tire size because it is really close to the same diameter as the stock 195-75-14s, so they would fill the wheelwell the same, except be wider. They are almost exactly the same diameter but almost exactly 2" wider.