Yes, PAG 46 is what you want, and is the equivalent of the Ford stuff. You are correct, 46 is the viscosity rating, in centiStokes (46 centiStokes @ 40ºC). If you are just recharging the system, I don't think you have to add new oil unless you see it leaking out somewhere. If there's a leak, the refrigerant will evaporate and the oil will stay behind. If you add new oil, you have to worry about not putting too much in since you will not be able to get 100% of the old stuff out.

1200-1500 rpm is fine. Just keep it stable. When testing, open the windows, turn on MAX AC, and turn the blower on all the way. Ambient temperature and system load have a much greater effect on pressures than just engine speed (hotter=more pressure). Standard pressures are usually listed for 80ºF ambient temp, so they should be adjusted slightly depending on the temp.

I don't know what color the fluid should be or if it has a dye in it (shine a UV light on it and find out...). I think it starts out clear and a dye is added from the factory in some cases (not sure). However, if it was amber or brown I would be worried about it being broken down.

Again, I would be inclined to leave the oil in and pump down the system, then recharge away.

 

If the system has been holding a fairly good charge and just needs a slight top off I wouldn't worry about adding oil.
If it has had several top offs due to a "diminimus" leak then I would add a oz or two. The system full oil capacity is 7 oz BTW.
Too much oil will reduce cooling output.