The guy I spoke to thought that the freq range (2250 hz to 2450 hz) I am concerned about should be attenuated effectively using that product, especially given that the cameras have camera stabilization. I'm trying to attenuate the vibration from the prop slapping the air.

If this product doesn't work he said that I would most likely have to look at fluid dampers -- much more expensive. I will avoid that as it would involve airframe mods -- attaching directly to the frame--which gets the FAA approval process involved and then our even more demanding internal approval. Been there. No thank you. We'd most likely just accept a lower quality product rather than go that route.