I don't run a hot-water system "yet".... but if you have 2 reels would 3 pumps and a small holding tank work....?
Main pump, say 100psi 7Lpm, to supply hot water to a small, well insulated 1 gallon tank, that would then supply 2 smaller, 60psi 4Lpm reel pumps.
Float valve fitted to the second tank to switch off supply.
It would save on having to heaters fitted.....
Regards
Mr H