Ok so I started playing with some "real" pleats like in the earlier link....followed it step by step. That guy is WAY more experienced than I, so take this for what its worth.... First, I couldnt find any 1/4 or 1/2 in scrim foam locally, and I wanted 1/4 thick on the 2 side pieces, so I got some headliner material (a little over 1/8th) cut it to length and l spray adhesive it together to get the 1/4 inch.
He wanted 1.5 wide pleats, and used 2.25 wide lay outs.... I wanted 1 inch pleats, and I used 1.5 for the lay out....my pleates are running 7/8ths wide. I think I should have used 1.75 for the lay out. (he is absolutely correct, these eats a ton of material) I laied out 42 inches worth thinking I would get 28, im going to be short....
On the next one I make, I am going to skip the initial top stitch on the vinyl, it seems redundant and difficute to match the same stitch line when attaching the foam. Also, I am going to just lay out the 1.75 on the foam. reason for this is that as you move foam pleat to pleat, the shrinkage of the foam makes it very difficult to match the lay out lines and the initial vinyl top stitch. On the one shown here, I stopped trying to match and just redrew the next stitch line. For me, it worked much better.
If this makes no sense, let me know, Ill try to explain differently...