Great video (along with your other AC powered BlueRail video). You definitely are at the cutting/bleeding edge. I looked at the Dead Rail Installs site for more info. I could not find any install instructions. Do they provide detailed instructions with the board? You mentioned trial and error . . .
This is what I was able to glean from the site and your videos. Please correct me if I'm wrong.
1. You are using the 5Amp board
2. You can use the board on AC power to run motor and lights directly (no DCS or DCC)
3. You can use it to run a PS3 (DCS/DCC equipped) engine with Battery power
4. You can add a DCC sound board to option 2
They sell the 5Amp board for $140. They sell "install kits" with a battery for $75. I assume you can supply a battery and connectors from RC suppliers for much less.