In general, flat is fast. Wind speed and boat characteristics will be a big part of the decision making process on where to place the crew. Light boats may place everyone on the windward side while a heavier cruising boat may do the opposite in the same wind conditions. Once you get past 15-20 degrees of heel the boat will begin to lose both aerodynamic and hydrodynamic efficency.
So what does it all mean? With a Tanzer 22 I would think that you are going to have people on the rail most of the time keeping the boat flat and in light air you may put a body or two on the leward side to induce a some heel. If you have bodies on the leward side and the rail is burried, that's a problem and not fast.