i use a header system and run off that in my home to a rad in my furnace plenum, a rad inside my old fireplace, my DHW exchanger and to my floor heat ( i do use a small pump to keep the floor heat circulating..that is the way it was designed)
i also have a rad in my games room in the basemnt that i use only now and then that is heated by my return water from my DHW exchanger
this is all on the main pump (taco 011)
however, i made another exchanger behind my OWB and i use a 50 foot coil of copper inside a 2 foot high12 inch pipe to heat my garage...my OWB water return line from the house feeds this exchanger before re-entering the OWB and i have a pump in my garage that pumps antifree/water mix through the rad in the garage...this way i keep this part of my system closed from the reast and only have about 10 gallons in the system so no need for too much anti freeze..( a small expansion tank is needed for this part of the system) also if i am not going to be in the garage for a few days i just shut the pump off and don't use it (saves on wood)