very good answers to my questions
Reman is ok I guess, better than used I would think. Is the refrigerant R134a? If so the oils is polyester and will suck up moisture like a sponge if left open.
You should change the drier if possible, but in a pinch you could dry it out in the oven at about 150 for a couple hours. Keep in mind this does nothing for cleaning out the trash.
The orifice should be in the small line just before where it goes into the firewall. There will be a nut in the line and a funny shape where it goes in. Take the nut loose and pull it out with needle nose pliers. This can be cleaned out with brake clean and compressed air.
DO NOT blowout the system with compressed air. That will just contaminate the system with moisture.
The longer you keep the vacuum pump on it the better. Moisture boils at a lower pressure and that will help insure a clean dry system.
Yes the gauges can be calibrated. Remove the face and turn the small screw either direction till the needle is on 0. Make sure the hose is open to the atmosphere.
