Get a cooler and convert. The double bucket system is terrible. Trust me. It will not hold temp, and you will have to use tons of rice hulls to avoid a stuck sparge on a normal beer. Forget entirely about mashing more than 14 lbs or using wheat/rye/oats. I put up with this crap for about 25 batches and the best thing I ever did was to upgrade to a 10 gallon round cooler with a false bottom.