Sounds like you are thinking about using spray baste. I like this method. I have not tried the Elmer's glue method. You can reposition, but not push to smooth out. There are many videos of the "best" way. I recently watched one in which 3 pool noodles were used. Looked good, but don't have pool noodles, yet. Gonna try this when I do.
Now, I lay down backing, then batting. Start in middle and spray/join in 2 sections, then 2 sections to the other end. Same for top.