I'd still say this is worth a try. It's certainly got to be a lot safer than attaching weights to the flywheel, and it is a bit more "guess-free" because it's self-balancing, and is certainly a safer solution. The trick is that there needs to be some flex in the rotating mass (1/8" to 1/4") for the system to self-balance itself, so the engine would need to be on rubber mounting points instead of a totally rigid mount base.
Their biggest balancers are 32oz (600-660) of balance capability. Two pounds... hmm... well, if you put two on (on one side? one on each side?) that would be 4 pounds of balance capability, which seems reasonable from what I've heard most people talking about thus far. An adapter plate that matches the shaft/key to an 18-wheeler lug pattern would be needed, but that shouldn't be that tough to make. The $199 price is for two of the discs.
Of course, the genset should probably be on the same "base plate" as the engine, so there may be issues where the center of rotating mass is not the center of the crank (because the generator is rotating, too, and perhaps out of phase with the engine's vibrations.) I think that this is a "you have to try it" kind of solution, unless someone who really knows what they're talking about on harmonic dampening wants to take a crack at an explanation. Even then, sometimes things work unexpectedly.
