Being fairly new to radical throws and 3D (not as young as I used to be either) I've been using 50% throw for low rates with 25% expo and I start at 80% expo on high rates. The 80% usually makes the plane flyable on high rates all the time so if I get in trouble and don't get it switched to low rates I can still control it. After getting some time on the plane I'll reduce the high rate expo to suit my taste. Like Wayne said eventually you'll set it to where it suits your taste.

Mike