I just checked mine - it's 3/4" thick. But I've got three of them that can stay up all the time. Around $11 at HD for a 4'x8' sheet.
I definitely would pass on the 1/4". You want to make sure it can stand by itself (just leaning against the wall) without sagging, if you're not planning to attach it. Also, you don't want pins to scratch up your wall behind it (if it's temporary).
I covered mine with Warm&Natural batting . For some reason 2 are white and one natural. :roll: More great planning on my part, no doubt.
I used the spray stuff for presentation boards. But I've read where people just pin the batting/flannel to the boards.
After I sprayed and attached the batting, I trimmed it to just over the edges.
Then I covered the edges all around with duck tape.
Why?
I don't really remember my reasoning at the time, but it did make sense. ;-)