Basting the seam joins seems like a perfect use of elmers SCHOOL glue. thats the washable stuff. I am going to give that a try. I use it all the time for bindings I always wash my quilts after I have finished as I feel they get dusty and the cat always seems to find whatever my current project is and nap.
I must stress however you only need a miniscule amount. I take a scrap of paper or fabric out of my garbage can and squirt a pool of glue out. I then take one of my flat head pins and draw a bead on the tip of the pin and place that teeny tiny dot on the binding. I then iron.