I just bought an ArcMaster 185AC/DC Tig welder and a water cooled torch for my home shop. My first project is going to be a dedicated water cooler.

I'm aiming for 50psi @ 1 to 2 gpm. I've already identified the light weight 115v pump I'm going to use. What I'm trying to determine is which type of radiator is going to give me optimal perfomance considering the low gpm and compact size? Is a "two pass" automotive heater core better than a continuous loop condenser? Intuitively, the continuous loop would seem best, but most of what I've been able to determine from research suggests the opposite. Objection is flow restriction and contact area of a 3/8 copper tube compared to the flat "ribbon" surface of an auto heater core/

This is a system with a half gallon reservoir, 12ft of cable/hoses, and a recommended (by the torch manufacturer) 50psi and 1 to 2 gpm delivery. The radiator needs to be no larger than 7" X 7" X 2 1/2". There are (two pass) automotive heater cores and "continuous loop" condensers (usually with 3/8" copper tubing cores) available to me in these dimensions.

Which would be the more efficient heat dissipator?