John, do you have the D2585's ? I can'tr get them now.
But to get to your question with me running 10", 11" and 12" rims the width depends on the bite you are looking for . Narrow is good for more MPH because it allows the tire to grow more ,but we changed to 11" and the 12" as we were making more power and need more traction even after the shift. GoodYear says we should not very more the 1" from tire size, but I think no more than 2" .
With our Heritage Jrfuel car we now run 12" but we have tried the M/T 33x10.5w/ 15 on the last set of 11" rims. I'm thinking of selling that wheel tire combo, right now I have too many tires , GY 2585, GY 1288 [ 33x12x15] MH 33x12x15, M/T 31x10.5 [11] x15 and we have not tried MH 31x10.5 [ 11] x15 yet.
Call me if you want more info. 805-444-4489
Jon