madhavank007,
I don't know much about your process, but the best advice I can give is:
1. Do not measure anything that you are not using. You will find yourself fixing tranmitters and meters that collect data that does nothing but sit in a spreadsheet somewhere.
2. Do not set your specs outside of your monitoring capabilities. I work with ceramics, and I have seen many specs set to 0.01, but measured with a an instrument that is only accurate to 0.1. That may be a little bit of an exageration, but you see the point. You either have to spend the money to get the right instrument, or relax the spec.