I ran into a few more stumbling blocks when I discovered I can't just send xPL messages to non-existent xPL devices and have my app grab them. Apparently, the xPL hub doesn't forward packets for non-existent devices. That means I had to create xPL listeners for each Audrey I want to send TTS to, like Medianet does for each player. I eventually got it all sorted out last night and have started some testing of it. If all goes well, I'll post it up here.
In the meantime, I've been testing my xPL/xAP/starCOMUltra scripting app. I've converted all my Floorplan scripts and have turned it off a couple days ago. After a few problems in my script, I got a clean run with it overnight, no small feat considering my system pumped out 21 xAP messages/minute and about 10 xPL messages/minute overnight.