Cruiser, you have a few different ways that would work. You could glue the new fabric down like the original as long as the foam is still smooth. If the old cover took some foam with it when removed, this may show once the new fabric is glued in place. A thicker fabric with a busier pattern, kind of like what was on the seat originally, may tend to hide these more. The larger the inperfections in the foam, the more they may show. You will need to be patient when you glue the fabric on, making sure the the glue is dry enough in case you need to reposition, but not so dry it won't hold well. Also need to kind of feed the fabric into the recessed areas, where the design pattern is in the foam, as you go. You need to have enough material down into the recess, otherwise it may want to lift. You just need to be in the right frame of mind and at a time when you know no one will be interrupting you for a while.
You might be able to fill the recesses in the foam in with additional foam glued in. you could then sand it off and make it like they were never there. I don't remember how much contour these seats have. If they are somewhat flat, you may be able to come up with a pattern for a cover that doesn't need to be anchored, like a seat in an older pickup.
If you fill the foam in, you could also add your own automotive velcro and sew the fabric onto the selvage edges of your cover, the same as the new style covers you mentioned. Sometimes when I make custom covers for older cars, I skip the listings and hogs rings and use this instead. This allows you to anchor the cover to the foam pretty much anywhere you want. I sew fabric to the backside of the black channel strip, then draw my pattern on the foam where I want the cover anchored. Then I cut the foam out just wide enough for the strip to recess into the foam, usually somewhere around 1/2" deep (depends on what you want it to look like). I then use hot glue on the foam and on the fabric I sewed to the backside of the strips. Press it in place, and your ready to anchor your cover to it.
Depends on how much time and effort you want to put into it. Hope this helps.
You might be able to fill the recesses in the foam in with additional foam glued in. you could then sand it off and make it like they were never there. I don't remember how much contour these seats have. If they are somewhat flat, you may be able to come up with a pattern for a cover that doesn't need to be anchored, like a seat in an older pickup.
If you fill the foam in, you could also add your own automotive velcro and sew the fabric onto the selvage edges of your cover, the same as the new style covers you mentioned. Sometimes when I make custom covers for older cars, I skip the listings and hogs rings and use this instead. This allows you to anchor the cover to the foam pretty much anywhere you want. I sew fabric to the backside of the black channel strip, then draw my pattern on the foam where I want the cover anchored. Then I cut the foam out just wide enough for the strip to recess into the foam, usually somewhere around 1/2" deep (depends on what you want it to look like). I then use hot glue on the foam and on the fabric I sewed to the backside of the strips. Press it in place, and your ready to anchor your cover to it.
Depends on how much time and effort you want to put into it. Hope this helps.