There's a lot of articles about low-loss headers. What I can't figure out is whether or not a low-loss header has a place in a small single zone residential hydronic mod/con boiler heating system ? Seems that an installer can optimize the flow through the boiler, but requires a second circulator for controlling flow through heating zone. Seems like a considerable added expense, hence I'd like to know if there's any gains to be made in a small single zone heating system. My heating system has a large thermal mass with cast iron radiators and large gravity feed pipes.