replacing a/c compressor

[revsnet]

Hey everyone
The a/c in my 98 astro had a slow leak so I took it in and had it charged with dye and inspected for leaks. The garage found that the compressor was leaking so they recovered the remaining refrigerant so it wouldn't go to waste. I am planning to replace the compressor and accumulator myself. I've watched a video and read up on what tools I need and how to do it. I am confident that I have a good enough grasp to get it done, but I have one question that I cannot find an answer to. Everything I've read says that when I take the old compressor off, I should measure the amount of oil in it. But they don't say why I'm supposed to measure it. My system is supposed to have 11ozs. of PAG oil. When I put the new compressor and accumulator on, do I just put in the amount that came out of the compressor, or do I put in the full 11 ozs.

[revsnet]

OK, I've got the compressor and acumulator off and there was no oil in either. Like I said, the system is supposed to have 11 ozs. Can anyone tell me how much I am supposed to put in the accumulator and how much in the compressor?