I board baste with 505 on a ping pong table, first taping the backing right side down. I then position the batting over the backing and smooth it out, prior to rolling half way. I then spray the backing and carefully unroll the batting and pat down. Repeat on the other side. Now I position the top, right side up, on the batting squaring up if necessary. Once I have it in position, I roll it up from the short side half way and repeat the above. I have had tops and backing with only an inch difference (I quilt my own), but had to trim my batting the size of the backing after spraying to see where to position, but was able to baste it perfectly centered.