I spent a lot of time with the 9846 trying to optimize its performance but their
are certain default mechanical mismatches between the horn and woofer that cannot be overcome.

Matching a massive slow 411 woofer to a fast 511 horn will cause smear in the midrange.
no way around it that I can see. crossing at 500hz 2nd order is pushing it.

The difference in efficiency between the 2 will make your volume control non-linier.
I don't recall any discussions about this in the past.
I have charts here somewhere that show, SPL increase per Watt increase, based on efficiency.
They are rather impressive because it takes considerably more watts to get a given increase
in volume with low efficiency compared to high.

These observations come from the purist camp of hi-fi but can be easily forgiven in other
applications like home theater where the bass output of these will rule.........(with a low horn setting)

GM, the speaker stands and cabinet refinish were already done when I got them. (nice).
I spent my time re-foaming and converting to bi-amp which was the only hope for this combination.