Hey all. I'm trying out a new setup because my GK 212MB combo amp cant keep up with all my pedals anymore. Specifically, it can't handle the low lows I get with the DOD Meatbox and Ashdown's Octadose. So i've bought a 410 cabinet and I'm looking at getting another cab (either a 118 or another 410) to produce those super low sub frequencies. But I'm pretty ignorant about how to get two separate cabs to work together properly for the job. What sort of specs should I be seeking out in a new head unit?