Interesting, just haven't heard about CVR and if you can, would appreciate some links. Haven't dwelled on the avsforum diy board for a long while, built most of my subs 10 years ago now. In any case, I'd still rather run multiple amps

Never heard of Sinbosen. Behringer sure, and have not used one of those due sloppy specs as a primary reason, but they bench test reasonably well (but not to marketing spec).
75% of an amp's output in what way? How is the percentage determined? Just not a good way to compare amps (i.e. via "percentage").