If the material you're mounting the PFA120 to is solid wood (not unsupported siding, wallboard, etc,), or plywood (and not a very heavy PTZ), I like to use the coated deck screws of the proper length. They cinch tightly and quickly, don't corrode, are cheap and you run in with a drill or driver with a Phillips bit. They grip the bit, too which helps when you're on a 16 foot ladder.
I buy boxes of 3 different lengths at Home Depot or Lowes.
That should be OK for a dome; if a heavy PTZ, I'd go with larger lag bolts and be sure to go into a solid stud on the top 2, the bottom 2 could go into plywood or OSB. Drill a pilot hole first, drive in with a hex- socket adapter that fits the head. Try hard to find the type with threads up to within 1/4" of the head.