Here is my thoughts----
Chains are for bicycles
Belts are OK if you plan regulating engine temp to a constant and tension the belt accordingly, if not then the gear gives room for expansion as the engine heats up. I set my blower belt tension by idler slippage and after the run it is tighter.
All in all, "harmonics" at our level is not an issue, but some members on this board can sure"pick the fly xxxx out of the pepper". Been running and a top competitor for over 20 years BUILD IT - TUNE IT - RUN IT