wing root strakes (not canard A/C)

Thanks to all who replied to my post about about building wing root
fillets to reduce some tail buffeting on my Stits homebuilt. I'm pretty
much convinced that some simple strakes mounted above and somewhat
forward of the wing root leading edge will do the job. Some aerobatic
birds and apparently RV-8's have benefitted from strakes like this.

My new question: Anybody got info on how much above the wing and how far
forward to mount these? Flat plate or curved to match the wing airfoil?

Thanks,

Wallace