wow so many ways of using Elmer's washable school glue! I don't have any hand/wrist/shoulder issues and it is no problem for me to squeeze the little bottle. I think of it as a good exercise (remember I don't have any issues that some of you might have) and don't find it necessary to thin it out. It is so inexpensive and easy to do, I'm very happy with it. I don't need it for my bindings. I don't pin them either, just smooth them out as I go along. I can do a pretty nice binding now.
One poster on here reminded us that it is to replace pin basting, not spray basting, so it doesn't have to cover every s inch of the quilt. I have had great success. I don't iron anything because since I quilt for my own pleasure I am never in a hurry. So I leave it overnight.