5/8"? not sure if they make a plate that will put the cleats in the right spot above the tongue.
Screw some scrap down on your chalk line to put in the first row. Screw it down good because the nailer will move it.
If you have to reverse direction to go into a closet etc. glue a spline in the groove.
What underlay did they recommend?
This is what I used
Bostitch MIIIFN Flooring Cleat Nailer, M111FN
This would probably work just as well
2-in-1 Flooring Air Nailer/Stapler