The following are responses I have recieved from the network about this plan . This makes interesting reading and some of the results have been incorperated back into the main plan. Many thanks to all who have replied. I just recently initiated a study of kite messengers to determine the most efficient design. My daughter is using part of this as a science fair project for school.
Tubing is taped underneath to constitute the release mechanism.
I use the front stop arm as the front hanging point. The dowel sticks out 1.5' off each side. The sail is held in position by lines attached to the lower outside corners and then to the release. Flaping definitely slows the return of the messenger. By adjusting the length of the release lines the sail's angle of attack can be changed.