Well as it turns out, a good friend of mine is a professional banner tow pilot. He flys a 180 HP Cub, and we have talked at length of how he goes about doing the low fly by and pick-up. Full scale has many other issues to deal with that RC flyers are not so worried about. I intend to greatly simplify matters by hooking the banner up first, and towing it right off the ground. I will lay the banner well out ahead of the plane, and just off to the side so as not to roll over the tow line as I take off. The drag will come on more gradually that way as well.
Hooking up at the tail just seems to be wrong...because unless the banner is very small and light... it will definitely act as a steering device, attempting to defeat turns to some extent. My 20 foot banner, or 5 foot X 6 foot flag, will be a very large size and I know that will create a huge amount of drag. I am tending toward a near CG hook up point in order to lessen the effect of the banner trying to overwhelm the plane.
jim