RE: Looking for Airfoil advice
Flaps and spoilers, yuppers. Thus, my comment up thread about simple ol' Clark-Y with flaps.
Not to mention they are a huge help on landing. Assuming of course that you have the runway length where the extra drag on takeoff is not a problem.
I have no idea what an S2-Tracker is, but it seemed he wanted to lift a lot of weight... The Wortmann airfoils with the cl of 1.6+ are used on the central section roots of major sailplanes. 2 reasons. 1) High lift where most of the weight is 2) High volume in the wing allowing a high section modulus for the wing root spar, or double spar setup. Well there are other reasons, but...
If he wanted a REALLY high Cl, could name a few giving cl 3.5+, but you won't find empirical data for low Re numbers on the web.
Got me. Just use the UiUC database in the sticky at the top of this thread. Download, peruse, ask questions on how to apply said data and move on.