After further review, and some basic setup, I'm quite pleased with this setup.

I dug out an old Stereophile test CD that contains in/out of phase track, left/right track, pink noise track, and warble tones from 2khz down to 20hz.

Discovered I had right and left mixed up, doh!
Discovered I needed to swap the polarity on the sub woofers, they were out of phase with the duplexes.
Using the pink noise discovered I needed to re-toe the duplexes to eliminate at least some of the comb effect at higher frequencies. In other words, broaden the sweet spot.

I also flipped the duplex boxes over to get the horns just a bit above ear level. Now I have to rotate the crossovers as they are upside down now.

Of course, lastly, dialing in the MF/HF pots on the crossover. My goal is to not "hear" the horns. Just to blend them with the woofer.
That said, I'm not hearing ills of the "high power cone and VC".
We know it's an R904-8 and is also used in the 604-168X, but only a handful of folks know the exact difference and they aren't talking.

Oh, I drew out the crossover. I removed the switch system that allowed the MF only control, so now it operates just like the M19 but of course is different. if interested, I can post it here.

Ron