Put the outlet so your EVSE is sitting at eye level. You're going to have to provide mounting points for the EVSE in any case so why not make it convenient for you to use? Also, I would use a red or orange outlet to make it obvious it's not a 120V outlet for someone who doesn't recognize the receptacle. You might also want to label it with voltage and rated amperage.
The 220V 20amp outlet I have in my garage is actually a little above eye level. The EVSE is mounted just below eye level.
2018 Honda Clarity Touring PHEV - Forest Green w/Tan interior (wife's car)
2017 Volt LT - Heather Gray; black bow ties, Charcoal VoltShelf
2012 Cruze ECO MT (hail totaled 5/8/17 103,600 miles @42.5 MPG)
2010 Mit Lancer GT MT (traded for ECO @31K miles)
2002 Pont Montana AWD - title to son at college graduation
1990 Pont Transport (traded for Montana @240K miles)
1986 Fiero GT MT (traded for Transport - needed more seats)
1985 Fiero 2M4 MT (traded for Fiero GT @8K miles)