I doubt it matters much on car value, but, like Jason, I prefer non rolled.
From a traction standpoint going down the strip, the length of the tire foot print is more significant than the width of the footprint at the same sidewall height when comparing adjacent tire sizes in many cases. That's the reason we see a lot of guys with 255 drag radials pulling such good short times. They also mph better.
I think most of us go for 275s for looks because we think they make the car look badazz. Okay, to a certain degree, they do! LOL
If I were to do it today, I would go for 255's, I think.
In your case, with 10" wheels, you probably need to go 275's to get the tire to fit to the wheel width. 10" wheels may be a bit over the tire specs but Cooper does not seem to offer much guidance. Nitto shows 9.5" max for their drag radials. That means rolling the lips.
Otherwise, you need 8" wheels and your choice of 275's or 255's.
You"re kinda in no man's land. typical hot rodding.