Hanging EMT conduit exterior to home
I would not use EMT at all.  It is not weatherproof.  Those compression couplers (you know, the not-setscrew ones) are not for weatherproofing, they are for better grounds.  I would either go with thickwall with threaded connectors which I would teflon or dope for watertightness, or preferably PVC, which is cheap and easy to work with.