Unless you are a purist , make your life easier.
I installed my seat covers by first buying some brass eyelets from somewhere like Spotlight fabric shop along with the eyelet tool. I then added the eyelets along the edges of the covers.
Instead of hog rings I used nylon cable ties. Much easier and I cant see them getting loose. Much easier to first install loosely then tighten all the way up when you are happy with the way the covers are sitting.
I still used all the listings that are in the seats.
2 other tips - spray your cushion foams with silicon spray to help the covers on and heat them up with a hair dryer or heat gun to stretch them and then they will cool and shrink.
Enjoy !
Frank.