Here are a couple of sites about the basting gun.
If the needle is long enough, bring it through both layers like a straight pin, it will hold the layers together tighter, instead of just front to back. You also don't have to worry about using a grid. I bought one because it is so much faster and I cannot stand for as long as I use to because of my back and knees.
http://www.quiltersreview.com/article.asp?
article=/review/product/010129_a.asp
http://www.dreamweavers-quilts.com/q...a-tagging-gun/
There are quite a few articles on the web, just google how to use a quilting basting gun.
Good luck