Buckling new seat skin problems

[70charginglizard]

I am a little worried about these new front bucket skins I just got for my 70 charger.
I got the old skins off and tried an initial fit test before I install all the hog rings and there not wrapping around the sides at the top very well.
I'm sure when the middle straps are used and the material is stretched tighter around the back and hog rings are installed it will eleaviate some of this upper material buckling problem but I'm still worried it's not going to take all these wrinkles out.
I'm sure it's just that the foam is so old it's shrunk down causing this problem but is there a way to fix it without having to re-foam?
My legendary interiors book shows that there soon going to be making the 70 charger bucket seat foam again but that's another 220 dollars. (I'd like to avoid that if possible) and what if when I call them they tell me theres a year and a half long waiting list.
That won't work.

Comments???

[68 RT]

On my 68 when I did the seats, I used 1 inch foam under the covers for the front seats. Turned out great. I first thought they would look too stuffed. But they didn't. Also after doing mine my front seats had some light wrinkles, let the car set out in the sun a couple times and they disappeared. Also lightly heat the seat covers this will help to stretch them tighter. And have good hog rings and pliers. Good luck! 

[jaak]

I have been told too if you cut out some 6" x 6" squares out of a garbage bag, and glue to all corners (upper right and left of seat back and front right and left of bottoms, the covers will slip on so much easier.