Everyone need to remember that the simple 'U' coil in a stove is NOT the same as an 'instant hot water coil' in a boiler.. The long, finned 'instant' hot water coil in a boiler will raise 50* water to 140* water at the rate of about 5-10 gallons a minute, if the boiler is at 160-180*.
The HilKoil 'coil' in a stoker stove will barely raise 50* water to 70* water if you are running the water from the street through the 'coil' to the sink. These Hikoil 'coils' are meant to slowly heat a 40-50 gallon tank of water to 140*+ overnight or during the day,, over an 8 hour or more period of time..
This is why a thermosiphon system works,, it is slow, but steady, and will keep a tank of water hot or heat a tank of water 'for free' overnight.
I would never run well or street temperature water through a Hilkoil 'coil' in a stoker stove.. use the coil as an auxilary heater for your HWH. Or best, add a tempering tank prior to the cold water inlet to the HWH, and use the 'coil' to heat the tempering tank.. this way the HWH never gets street or well temperature water,,
Any way you plan on plumbing it, the small, in-stove coils do not turn the stove into a boiler,, there is just way too little heated surface.. I think SteveN told us that a HilKoil 'coil' was good for about 5K btu per hour.. not a lot. [ my memory may be off on this number, but it was a small number]
Hook it up as a simple thermosiphon, if you are not happy, install a small circulator in the loop. Either way you are storing heated water for your morning showers, and afternoon/evening laundry... [at least that is how it would be in my household].