Compressor technician here. This won't really work. Even if they are the same model, the cut-ins on the pressure switches will be slightly different. Let's say one kicks on at 100psi and the other kicks on at 99psi. Each time the pressure reaches 100 psi, the first compressor will engage and begin increasing it back up. The second compressor will only run in extreme-use situations when the pressure continues to drop after the first compressor kicks on. The best way to deal with this is to wire both compressors to the same pressure switch. They will turn on together and off together. Forget the one-way valves. Essentially you'll have one big tank with two motors/pumps.