If he has a bad head or gasket, wouldn't there be a visable leak? He said he's losing about an inch every hour, thats quite a bit.
He said the coolant was coming out of the two tubes by the radiator, I don't believe that would be caused by a bad gasket.
I'm with Loco on this one, sounds like something is getting pressurized. Possibly blockage somewhere.. When you drain your coolant do you flush it with anything other than distilled water??? If you use tap water, over time the minerals in the water will stick to your radiator, clump up, break lose, and plug something.