I would stick with his layout. I dont really think a little pre-exhaustion of the arms before you hit them is a problem because most muscle hypertrophy occurs under stress/exhaustion.

That would not be advisable. If you want to focus on your arms, do chest and back on Day 1, Legs day 2, bi's & tri's on day 4, shoulders abs and calves day 5. This will allow you to give full strength to chest and back, and while doing so hit the tris and bis secondarily. When day 4 comes around you'll hit bi's and tri's a second time at full strength.