...if specific manufacture data not available some suggested settings are high temp 10-12*F SH, medium temp 6-8*F SH, low temp 4-6*F SH.
I think these are reasonable, as long as the suction piping runs are long (like supermarkets). If the system has short runs or has capacity control, I would tend to stay with the slightly higher values of 8-10 as a minimum range.

Having said that, and as stated by Steve, if you can control a minimum suction superheat (at the compressor) the compressor discharge temperature can be much lower, than when used with a higher suction superheat.

The discharge temperature is a good one to get used to recording. After you develop a feel for "good" temperatures versus "bad" temperatures, it can really help nail down the best superheat (suction or discharge) for the system operation.