I am sending a couple of photos of wall hangings I have done on felt without any puckering. One uses 5 designs to make a large 16 x 23 inch one, and one uses 6 designs to make a large 12 x 15 inch one.
I only hoop a piece of Stitch n Tear stabilizer by itself, adhering it to the inside of the inner hoop ring with sturdy 2 sided sticky mounting tape. The felt is held in place using a conservative amount of spray adhesive. I use the minimum amount of tension in the bobbin, around 12 – 15 grams and the upper tension just enough to bring the stitch thread to clear the throat plate and let the stabilizer alone drag the thread to the next stitch. When you are done the fabric does not want to return to an original non tension state and remains stable.