Metal lath to block--nailing pattern

I'm going to power nail paper-backed metal lath to a heavily painted concrete block exterior for a whole-house stucco installation. I anticipate using a TrakFast power nailer with 1" disks. Too much to drill-and-screw.

Any suggestion on pin length (available from 1/2" to 1-1/2" in 1/4" increments)? Also, what is the recommended nailing pattern on a concrete block wall?

Thanks guys,
Chaz