No need to drive in circles, I'm sure someone in here surfs a boat like yours. Hopefully someone will steer you the right direction. Put at least 60% of your weight in the back corner you surf on, 30% mid ship (side you surf on) and 10% weight up front in the bow (side you surf on). You should be able to throw a godd ridable wave with that configuration. I would set it up like this, Keep in mind I dont have a Supra, but this is what I would try.
Rear corner locker 750# sac, Mid ship 400# sac, and the 300# sac in the bow, all on the side you are surfing. Also if you have a center ballast, fill it all the way. Good luck, and happy surfing, and PLEASE don't drive in circles. That does nothing but wash out the lake.