Good luck with your cabs. I'll look forward to reading some reviews!
That early HT series from Berg was interesting. The HT210, HT322, HT210s/HT122s stack, HT212, etc., were big, heavy horses, and IMO took a unique design approach. The woofers were those hi xmax type of drivers (or at least they sounded as such, and you could really see the pistoning in there but they took massive low end without breaking up), and the cabs were tuned very low... lot's of deep low end to my ear. As you know, whenever you spec a woofer to go that low, and put it in a big box tuned low, the upper mid response pretty much disappears from the driver. Andy at Acme deals with this by adding a little mid driver to 'plug that hole' between the top end of the woofer and the tweeter. Jim took a different approach and used a big honking PA type horn tweeter that seemed to be crossed over very low to 'plug that upper mid hole'
The result was 'interesting'... deep bass, relatively polite mid mids (these cabs were more big and smooth than 'punchy), and an unusual top end response that had upper mids/lower treble and upper treble coming out of that big horn. That gave these cabs a very, for lack of a better term, 'hi fi' tone... deep bass, polite lower mids and mid mids, and a very, very clean, crisp top end.
I liked these cabs way more in the basement than on the gig myself. Pure IMO there, and FYI from my perspective.