You can change the resonance of the TB too just by adjusting it's tension - a tight TB will have a higher resonance frequency between a given pulley distance, while a loose TB will have a lower resonance frequency between a given pulley distance.
A tight TB places additional stress on the belt and crankshaft, cams, pulleys, etc and wastes power. A loose TB runs the risk of skipping cam or crank pulley teeth. It took me a long time to go through Kaz's EXTREMELY helpful videos and adjust my TB tension (out of the car too) to where he recommended it. Without the correct test equipment, who knows the effect the tension adjustment has, and also the effect of the heavy OEM pulley.
The harmonic dampener also plays an important role in protecting your oil pump gear. Small crank end resonance oscillations can result in over-stressing the gear. Again, I don't know what that resonance is - I trust ATI for my engine.
It's interesting that when doing the resonance calculations, it's always assumed that the other end of the crank is basically "fixed." This is because it contains the much heavier clutch assembly (relative to the harmonic dampener). When you drastically change the clutch/flywheel weight, you are potentially shifting the crankshaft resonance frequency and amplitude out of the range that mother Honda designed the OEM harmonic dampener for....
I looked at Billy's case when rebuilding my engine... IIRC it was a used crank from Japan. There are too many variables based on past usage that I couldn't pin the failure on one thing. Therefore, I stuck with a relatively heavy clutch (RPS carbon that was balanced together with my crank), went with an ATI dampener, and I also hand-radiused every sharp edge on the crankshaft before cleaning/polishing/balancing. Those edges are extremely sharp and are significant stress-risers. I guess you could do some surface stress-relief if you wanted to with local peening, but I thought that was way overkill.
I'm disappointed with the 90-degree V6. I understand why Honda did this (for their future V8), but it resulted in a weak crankshaft with 30-degree crank pin shifts in order to quell vibration. I don't have the money for a nice billet crank, so I tried to take care of what I had. I'm sure I am pushing it's limits.
Bottom line is it's hard to go wrong with a new OEM dampener, or an ATI. I would not use a solid pulley.
Dave