Use some Elmers glue, no need to use Roxanne's Glue Baste It glue....it is the same product.....Elmer's washes out when you are finished. Hope this gluing helps get your edges where you need them.

Best board ever to learn about all things quilting and sewing.

I'm pleased that it worked for you; sounds as though you put a lot of thought and effort into getting it right.
I reckon it's one of those lightbulb moments and once it's been switched on for you, you'll remember it in the brain/hand memory thing next time :D

Mary