Blend door foam, non Porsche question Options

[narino]

My apologies if this is posted under the wrong topic section. I'm tearing my hair out and stuck. Unfortunately the mustang forums I post to had no replies.

I'm working on my other girl's heater core (91 mustang), and decided to redo all the foam on the blend doors. I saw on the interwebs that older cars supposedly had used 100% wool felt prior to foam becoming the popular material of choice. So I bought some, and stuck it on. Unfortunately the felt is too thick and it's not letting the door make a good seal when closed, see pic below. I have not been able to locate any thinner 100% wool felt. Supposedly the readily available 100% polyester felt found at craft stores will deteriorate after a few years. I also read the open cell foam from the big box stores would also fall apart after a few years. I really do not want to do this job twice. So here I am, with less hair and stuck.

Does anyone have any tips or a source for some felt or foam that would work for this application? Any insight would be greatly appreciated.

Thank you,

Jorge