Section 314.23(H)(2) requires "wiring enclosures within luminaires used in lieu of boxes" when supported by a single conduit to be "prevented from loosening by the use of set-screws or other effective means or" at least 8 ft above grade, and shall not exceed 12" in any horizontal direction from the point of conduit entry.
So you are probably ok on the length, but the reflector can't be larger than 24" across.
