Yeah, LOL made in the 70s...amazing what you find in the stash when you clean up, isn't it? :lol: Maybe I should change the name to retrodork LOL.
In any case, the flannel should work, especially the cheaper flannelette (think walmart flannel compared to your quilt store flannel). If you have to buy it, see whatever is less expensive...the other person I talked to online did suggest the felt but I wasn't about to blow my fabric budget for the month on this project. I'd say the $25 estimate was about right. I washed and dried the fabric first and ran the dryer again just before I put it on...oooh the joys of static cling!!
I didn't spray mine with my precious spray adhesive. Just put it down on top of an old poly blanket, cut it oversized tucked it to the backside and started stapling. Quick, easy, cheap and such a bonus to have!