Randy,
I know exactly what you mean. Much of the top grain "skin on" leather varies in thickness quite a bit. Splits on the other hand, sanded rougher leather used on some pasted strops tends to be much more uniform due to the sanding process that removes the skin layer.

The sanding idea is a good one, as is simply being selective, something a large manufacturer can't take the time to do. I do think one advantge with the narrow strops is a lack of uniformity is not as significant as with a 3" wide piece.

Tony