Hi Brad,
I use a rectangular cooler (esky) I started off with a copper pipe manifold and was getting around 70% eff. A friend gave me some S/S mesh so I made a false bottom and am now getting 80% eff. I have found that I get a smoother run off with the false bottom and no stuck mashes even with a wit beer (your recipe) using 50% wheat. By the way that was the first wit I have made and the aroma from the orange peel and corriander was magic, it's fermenting now.
Regards
Andrew