I am looking at buying a used Hardy H4 owb. I would like to heat both my house and dettached garage with it, totalling about 3200 square feet. I am planning on running 1" pex to the house, for the garage I plan on using a 60k btu hanging heat exchanger. For the garage could I get away with 3/4" pex? And can I use a T off the pump on the boiler or should I use separate pumps? Thanks!