Since all of this, HLConvolver's developer has confirmed there is some kind of defect with the visualization.
Based on that info, I'm guessing the newly added Steinberg parameters exposed a defect in the plugin's visualization. Anyway, this visualization issue threw me for a loop.
I tried to confirm what was going on by hooking stuff up external to JRiver but ran into another defect where windows wouldn't recognize more than 12 channels with my DAC's WDM driver.
I need to retest, confirm channel output and ignore the visualization.
I think the approach of a dialog sounds good as there will always be some new configuration. Just a matter of time before someone adds a 3rd sub.
I'll retest paying attention ignoring the visualizations and confirm channel output for 4.0, 5.1, 5.0, 7.2.4, and 7.1.4. Might take a bit of time, but now that I understand the issues I think it should go better. Thanks.