What is the best AC compressor capacity which suit my project? What do u think? be kind to help me..! plssss?

The simplest answer is it shouldn't be done. The Benz equipment was designed for freon 12 or 134A and unless you use an automotive compressor, the compressor will operate at too high pressure. It will probably blow out the condenser. The work will also require special equipment that you probably don't own.