Just checked my cabonet and the sheet I have are 1" high , 1" wide and 3 -3/4" long . I got these from A&A Industries which make large aircraft kits of the old Bud Nosen Kits.

Mr Mulligan was mine which has a 9' wingspan. The cowel they gave you in the kit needed the blisters installed on it.

I ordered a cowl that had blisters already attached but they gave you them to install.

Check the net for their site . If they can't help , I'll send you a couple of the ones I have.

Tony