I am a little confused about power setting options on my Piper Turbo
Arrow from my power setting table.

Assuming I want 75% power, at Sea Level, I can run it at:
1. 2300 RPM and 34.8 inches manifold pressure
2. 2400 RPM and 33.8 inches
3. 2500 RPM and 32.8 inches
4. 2575 RPM and 31.5 inches

How does one choose between these settings. Are they completely
equivalent? Is one setting easier on the enginer or props than another?
Of course, I could do a whole bunch of experiments, but if someone has
a good rule of thumb and a simple explanation behind it, I sure would
appreciate it.

-Sami
N2057M, Piper Turbo Arrow III