Of course the best thing would be to try both sizes and see which you prefer. Because, as I have no doubt has already been mentioned, the difference between a 2.5 and a 3 inch wide strop is little more than personal preference provided the quality is there.

Windshield wiper strokes, C-patterns, Obie strokes, whatever you'd like to call them, are a result of natural ergonomics and the arc created when your elbow is fixed at a point in space and you move your razor along the strop. It is a very safe stroke since you are only moving your forearm and maybe a bit of wrist. Keeping a razor moving straight on a strop requires movement at the elbow (from the shoulder) as well.

James.