I use rubber bands on my Alpha and I have not had any problems with the wing lifting up off of the wing saddle. Even if I am doing negative G maneuvers, however I am getting kind of tired of using the rubber bands, so I am contemplating on adding wing bolts at the same time that I add a 2nd aileron servo. As far as converting the avistar I really don't have any experience with that aircraft , but if it is similar to my alpha then it should not be any problem. Whatever your decision , may you soar with the eagles with your feet firmly planted on terra firma.