Scott,
We founded advice as I see it. Things were done a certain way for a reason...often because it was "best" or sometimes simply because it was "good enough".

Personally I find a 2 1/2" strop plenty wide and many felt the X pattern was needed. I also just like the proportion of the narrower piece. While I don't think cupping has been a big issue with mine, in theory at least wider may be more prone to it.

Today the 3" seems the strop of choice now days as is a 3" Norton. Both are easier to use than say a 2 1/2" or 2 1/4" but are they better? or are we giving up something by going wider?

(BTW, I'm don't warm my car up..a 1995 Saturn with 200,000+ miles on it. I figure it's only got so many hours of life left and I won't waste them sitting in front of the house)

Tony