Some clarification on this new balancer please?

I threw the outer ring on my Magnum harmonic balancer/damper and this one was recommended by Summit racing.
Problem is, the sales guy couldn't tell me which weight to use for the Magnum, nor if there were specific instructions included with the balancer on which weight to use.

PRW High Performance Sportsman Harmonic Dampers 2331841

Anyone know for sure?

Thanks