I second the sticky disk ones. As you are apparently very interested in flow, I think you would benefit greatly from telltales, especially on the head sail.
Your sail may look full, but the tell tales do just that, tell you what part of the airfoil is stalling. If you enjoy screwing around with sail control lines
, as I do, they give you lots of oportunity to play with trim, twist, etc to maximixe the amount of lift.