Wow! 32 feet of radiator hose!! You've got to have a circulation problem, and my bet is you've got air trapped in the system that is restricting flow. With nine gallons of coolant you shouldn't be seeing 220F cruising temps unless you're holding back the hot coolant from getting to the radiator. My first thought was that you may need to take the stock water pump out of the loop and just use a right sized electric pump? How did you select the flow capacity for the helper pump? I'm thinking two pumps in a closed loop may be your problem - one may be cavitating - but I'm not sure of that yet