George,
We have a MM360 as well and a hood w/ makeup air, although our makeup does not heat or cool the air coming through. How could we know if we are better off leaving the makeup air off in order to make it easier to heat or cool the building. The current AC that we have is undersized for the shop, upgrading would involve moving to a roof unit vs our current (4 ton?) unit we have. If I recall, we would need 8-10 to properly cool our space.
Dan