We landed, and discussed the problem. John and Harry had suggested vortex generators across the front of the ailerons. Harry installed them in just a few minutes, made and quickly applied with aluminum tape. These were located on the wing at the root end of the ailerons only. Pictures reveal straight tufts behind the vortex generators, with spanwise flow starting outboard ofthe tufts.
More testing is in order.
I will attempt to organize some of the local Varieze's to fly with tufts on a weekend to get a better feel for how consistent the separation is from airframe to airframe. Will let you know the results, and any fix that improves the bottom end, without undue impact on the top end. Harry Abbott recommended to check out the boundary layer flow behaviour using tufts taped to the wing's top rear surface on, ahead, and outboard of the ailerons. And so we did. We departed from 27 Ramona as a flight of two on Sunday morning and climbed into a clear, cloudless sky to about 7500' to start the fun and games.