I'm with giddeon. Hard to picture. Outlet goes through wall? Do you have your portable unit suspended horozontally with the outlet portruding through a hole cut in the wall lol?
Sounds like your outlet is more of a hose type outlet so you can just cut a circular sized hole in wall and stick hose through circle? Guess you're just not describing it well enough for us high guys.
I have a portable on wheels and can't figure out how I'd run it in the other room and cool my g. room.
My 2 hose unit ducts through ceiling and vents to attic. Therefore no heat from exhaust heating my room or adjacent rooms.
B.T.W. your 7000 BTU unit will work ok with 2 lights this time of year. Come summer time its a way different story depending on where you live of course. For 90% of us, 7k BTU would not be close to enough for 2 lights in summer, even without CO2.