I made my bags(plural)from vinyl , closed with velco and Morgan sew on badges. The bags look like envelopes. I decided on a bag for each sidescreen a) to stop rubbing and b)so they are easier to manipiulate into the slot behind the seats -= mine is a sport model with a handy space where the spare wheel should go.
They will also go behind the seats - one behind each or together on the rack if needed.
Used a special strong sewing machine needle with thickish cotton for the sewing.
EVEN MEN CAN MULTITASK!!!!