I used to have 200 Kliegls and we did convert to the FLKs, the gobo holders are an odd size and gobos never worked good. We used pie tins and made holes or slots for breakups.
We did a test in college with the engineering dept. We could never break the fitting, the mounting always broken first. I think we got it past 6 tons before the mounting broke loose the last time. As people said, it is all in the mounting structure and fasteners.