After seven days, I have given up hope of any reply. I bought an RS210 anyway. Might eventually buy a second amp head and an RS212 for Billy Sheehan-style dual channel effects. TTFN.
I've posted similar requests for info and got nothing, but by digging around I found the probable reason why TCE will not publish any detailed specs or graphs on the Speaker Cabinets:
It's due to the relatively small dimensions of the cabinets and the speakers used, in order to get any decent bottom end and to offset a mid-range hump the TCE Bass amps are electronically compensated to work specifically with the TC Speaker Cabinets inherent limitations and defects (which probably also involves the crossover network too). So that anyone using the TC speaker cabinets with another vendors amplifiers would not get the same performance and sound stage that would be delivered by a complete TCE Bass rig setup (Amp & Cab combination).
The only way TCE can refute my contentions is to publish the specs and graphs, something they are normally very good with vis-a-vie their studio and broadcast equipment (though again very noticeably absent from their new guitar toys), so it''s absence here is quite telling. There is obviously techy stuff they don't want to talk about, and so let the marketing and endorsers do the sales pitch grunt work for the products. This however should not detract from what most reviewers and musicians (pro and amateur alike) consider a really great piece of kit.
Ergo dead silence from the sales & support people, as this works in TCE's favor to promote their package over the competition ("it's about the sound, not the numbers" approach).