I recently quilted a 120 x 122 inch quilt on my old Bernina. I know everyone says to cut waves; but I cut straight. I used the heat bond tape, as you did. I used lots of pins and checked that the backing was smooth before I started. I added the batting on the side as I was ready to quilt it. In other words, after I had quilted one side, I then added the batting to the other side. This worked well for me. I will probably do this again on the queen size quilt I am making.