Is there a reason you are capping yourself at 72v nominal? I would at least go with the 841800 i think it can only help with either the efficiency knowing the controller can handle more or just the fact that if you want to go up to 24s on the battery u have the capability
Having two outputs is that if you are running two controllers? Which I would assume just means you have to use pins 1 2 and 3 for the throttle to function properly?