AI sols are really nice, love the color they offer. That's beside the point though. The fixtures are 2.35 inches high leaving you 2.65 inches left. It's recommended 12" above the water level for good coverage. You might need another fixture in that case. If you do, it might be cheaper to not use the canopy at all and hanging them.
This person says they have "two SOL Blues over a 60" long x 18" wide by 23" deep reef mounted 12" above the water and the coverage is awesome with no dark spots or shadows."
AI Sol LED Blue Module - The Reef Tank