Yes.

I would prefer to avoid the expense, and the installation will be difficult. But that may be the way I have to go.

Theoretically there shouldn't be any "ultra-hot" water. Each tank is thermostatically controlled and should be at the same temperature. My thinking is that by lowering the temperature of the output tank, it will be easier for that tank to maintain its set temperature, even if the water from the pre-heat tank is temporarily at a lower setting.

I'm going to try that and see what happens.

tanstaafl.