Is it possible to use midi omni for input when using Aria in standalone mode. I sometimes hook my guitar synth up and have to use individual channels for each string. Of course I can route Aria through a sequencer and use midi omni, but sometimes standalone can just be easier for quick playback.
If I've understood your question correctly, you can select "Omni Mode" by clicking on the MIDI channel indicator for the desired instrument (rightmost indication in the instrument loading "lcd strip" at the top of the player) and selecting "OM" from the resulting menu. I'm not an expert on the Aria Player's inner workings but it should then treat your six channels in much the same way as a six part chord from a keyboard controller. You shouldn't therefore experience any performance or latency issues, although this may depend on the implementation of your MIDI and audio drivers.