Visualize guiding the strap straight onto the roll with your free hand, or having to dig out a twisted strap that has wedged itself down into to gap along the side of the drum. You want to be able to see what you're doing while standing next to the winch. Normally, winding the strap onto the top of the drum will facilitate your work. If you're less than 4' tall, I'd wind the strap on the bottom.