A/C...putting back in after many years

[hrhoward]

Hello,
I HAVE to put my A/C back in. To fricken hot down here. The A/C has been out of my car since '95. The condencer and lines have been hanging on the wall, one compressor on the self and one still on the car. I have a new expansion valve, and receiver. Both still in box. I even have plenty of R-12 to do the job. What I would like to know is this; what size / style o-rings do I need, advice on determining which compressor is in better shape, tips on putting everything back together before I have it leak tested. If anyone can help, I shure would appreciate it.
Thanks,
H. Howard