Since you are staying with R12, there is no reason to use anything except mineral oil. It is cheap, available and does a great job. If you had it in your mind to be switching refrigerants then there might be a reason to use a more expensive choice.

BTW, since you are replacing the compressor, I trust that you have THOROUGHLY flushed the system of debris. If you have not and you are replacing the compressor for any reason other than seal failure, you will almost certainly be replacing the compressor again very soon.

Good luck,