I am planning to install 5/8" X 9 inch wide engineered hardwood flooring over cdx plywood by using bead of bostik pro-msp adhesive and 18 gauge L-cleats instead of full spread, i will really appreciate if some one can give me some suggestions.

If you glue without a full spread, you will have the best luck by a quarter inch bead on both edges and a serpentine bead between. Fasten every 6 inches along the edges and the tongue at butt-joints.