Well in theory it seems that you should lower the tab on the opposite side that you want to surf on. I could be wrong, I don't have one. But if you lower the tab on the opposite side it would push the other side of the boat deeper in the water thus creating a better surf wake.
I know there are few guys with new boats that have the surf tabs, hopefully they will be along to assist you.
Gone, out doing soft recreational past time with overpowered boat!