1970 Dart Swinger 340 bucket seat HELP needed

I'm getting ready to restore a set of 1970 a-body buckets seats for my 1970 Dart Swinger 340. Here's what i've discovered. The correct molded seat covers are available but the specific foam for that style seat design is not available from anyone. So my question for those of you that have done your 1970 Dart Swinger 340 buckets seats, what did you use for foam and what did you have to do to make it work? Molded foam is available for 1970-71 B and E body and molded foam is available for 1970 Dusters and Demons. Thanks in advance for any advice and help you can offer me.