I finally got around to testing and recording the effects of VGs. The test used three setups (hatch spoiler, VGs, stock hatch) in an A-A-B-B-C-C format, using the same stretches of road. The tests were done with the least amount of time possible between trials. Tuft testing shows full flow detachment with the spoiler, full attachment with the VGs, and attachment along the sides for the stock hatch.
With spoiler:
With vortex generators:
Stock hatch:
After looking at the videos, I can hardly tell a difference between ANY of the setups. Hopefully I'll be able to see a difference when I make the full Kammback.