Ed, I suggest using only a couple of drops of ArmorAll if you are going to use it. I wouldn't add it myself.

You probably know how to set your highspeed nv a few hundred rpms rich already. Either way by ear, or a dependable tach is fine. A tach is more accurate if it is a quality one.

You may be right about the highspeed leaking air somewhere. I wouldn't hesitate richening the low speed just a little bit too.