Don't cut anything until you have a matching set .
Once you get all the parts together you want to do both at the same time it only takes a few hours . you can also measure ,cut,bend,and weld on headrest frames using the spare tubing you cut from the center of the bench seat so it all matches ,Your "new buckets" have to be reinstalled back in the truck to tack weld the headrest frames in the correct position so they don't hit the back of the cab or window when the seat is pushed back . this whole process takes time and you still have to find a shop to build out the upholstery from the bare frames .I have extra sets ready to be upholstered that I can list in the classified section if someone wants a finished set ready to bolt in matching their interior .