Dude,
Bite the bullet and buy the Kexby seat covers. They came with my new truck. They are cut to actually contour the seat perfectly. Better than anything I've ever seen on any rover.
I hate seat covers normally. I had LR Waterproofs on my classic for no other reason than to not destroy the leather once i started wheeling on the east coast. The seams tore almost as soon as i pulled them out of the bag.
You'll never buy another set of covers. Promise.
Unless of course, you kill this truck too.