go a head and get your tire put on there and then see what width fender you think you need/want. If you want a tight fit on your tire you may need to fit it where and how you want it and shim it off of the frame abit. thats no big deal.
the other consideration is do you like a more rounded lookin edge on the fender or more of a squared lookin edge on the fender? the edge I'm refering to is the roll from the fender top to the sides. some are more rounded than others. the tire profile itself might tell you which one would look best.