I have some suggestions (from my own evolution on quilting). #1 We had a good quality 4x8 ply (with 4" cuts on the corners) that dh would help me put on the dinning room table when the family came for Christmas, etc. We pulled apart table but, using blocks and screws put the ply on top and had a table big enough. I used this for quilting for years.
#2 Then I bought the white folding tables from Joann's. They take up very little room to store and fold out to about 3x5'. There were some complaints about the fact that the fold out legs would move, but I put on little squares of industrial velcro and that took care of that. I love those babies so much dh got me 4 of them before I yelled STOP. But now I have a space 10x6' to work on when laying out a quilt sandwich. Makes me feel like a queen! And they store in a space about 4x3'.
#3 You could also use one sided fusible fleece and lay your back on that, smooth carefully and iron lightly until you also have the top on. If you still find a wrinkle you can reheat, remove and replace. It is an easy answer. Hope this helps