Glad your demo went well. I'd love to visit them some day.
I've never seen measurements of the 1234AC in the vertical configuration, so I can't say how it would compare to the 8361A. However, just looking at the measurements that exist, it doesn't seem to be as well-refined as the Ones. You would have to mount it into your wall to get the best out of it.
And it would be able to deliver satisfying bass down to 40Hz, but it is still a far cry from the NSW's you already have, even in a sealed configuration. There is just nothing that will compare to a 21" cone with 21mm of xmax and a 6.3" voice coil. You already have them, so you may as well use them.
It was great. If the opportunity presents, you definitely should!
I would be mounting in a baffle wall (I left that out above) and that is why their comments were that they thought it would be similar.
You are correct about the NSW....I can certainly try a sealed box for them and test it out. I will check out how high up I can run those as well, without running into too many issues integrating with the 8361. If that worked out, it would certainly be a money saver to use them and the 8361 vs the 1234A(which are like $13k each). I'm sure I'll do the demo of the 1234 and likely go back and try the 8361 without the woofer stands just to see. I'll also need to study more of the specs on them and the crossover points with their own drivers.