High pressure from the tank to the generator will use a smaller line vs low pressure. At my hunting camp my supply is high pressure 3/8 and about 75 feet. On that line I can heat,cook,hot water, 4kw Onan gen set all at the same time off the 3/8 soft copper line. At my house the tank is about 100 feet and on the 3/8 high pressure feed it would run a furnace, dryer and cook stove with no issues.