Hi Kyle,
Thanks for the update. I also saw your video on YouTube, very cool!
With all the hurdles Garmin keeps putting on their equipment I’m really second guessing the idea of getting a GNX375+G5-hsi. Pretty absurd that you can’t have the gnx and the sl30 both drive the g5 when their original release (experimental) supports this. Not being able to load frequencies from the gnx375 to the sl30 when the aera660 can do it is just the cherry on top...
As far as your audio situation, you could just have the audio from the aera660 go directly to your headset via Bluetooth, I doubt your passengers want to hear “Terrain! Terrain!” anyways. Now that you have Bluetooth on your panel nothing is connected to your headset Bluetooth right?
Alternatively, since your sl30 has built-in vor Morse code identification and without a cdi (slaved to it) you’re not using it for primary navigation, then you don’t really need to listen to its nav audio so your nav1 input in your gma345 could be driven by your aera660 audio. If you want to listen to an FSS you got your kx155 (but who talks to them anyway if you got adsb). This way your aera660 alerts would override the Bluetooth music instead of having to pick one over the other and they could be easily disabled with the push of a button on your gma345. If I remember correctly, @Bob_Belville has his angle of attack audio alerts routed to the (unused) DME audio input of his gma340 so you would need to label/placard it like he has.
Would definitely like to hear how it goes with the rs232 connections between your aera660 and your sl30/gnx375. Keep us posted!
Oscar