I use this method for binding all the time. It's great! When using the iron on the glue, just use the tip of the iron on the binding only. If you put the iron on the quilt you may flatten your batting and it won't come back up even after washing.
The metal tip on the glue is actually the pencil end of a mechanical pencil. You don't really need to buy the special bottle tips. Just pry off the orange tip of the glue top and "screw on" the pencil tip. I've not found any place to buy just the pencil tips but you can order the same "Sharon Schambers" glue kit from Plaid, that's what I did.
I'm told you can use the tips off of the Bic Mechanical Pencils, but I've not tried those.
To clean up my pencil tip I just let is soak in hot soapy water for about an hour and voila all the glue is gone.