I've been playing around with a single 24" loop from Hilkoil, and also passed it through a 40 gallon tempering tank and got similar low hot water output at an idle fire. Even with a full fire, I think that two, three, or even four, Hilkoils installed in the stove, would allow me to use a dump space heater, a small section of radiant floor heating, or a hot water to air heat exchanger, in the duct work.
I did cycle my one 24" loop, that went to the 40 gallon tempering tank, through a 22" x 22" water to air heat exchanger, and was quite surprised how well it did work, but with one coil, it couldn't keep up with the demand.
My tank temperatures would stay around 150 degrees when I didn't use any water or cycle it through the exchanger, but soon as I cycled the water through the heat exchanger, the temperature dropped to 75 degrees. When I used hot water, the tank would drop to 95 degrees. It would also take about 12 hours to reach 150 degrees.
So, all of this experimenting around leads me to the conclusion that more Hilkoils installed into the stove would provide the needed heat output I need. Go ahead and put another one in and see how much it improves. You do have to remember, at idle fire, it still may not give you the results you need until the stove is cranking some.