Sorry, I no longer have the Bravo V2 amp I bought way back when. It's gone.
If you want help troubleshooting, I'd recommend drawing a schematic that shows the circuit with your mods, and showing the voltages you measure at each node.
The 12AU7 heater should be as close to 12.6V as you can get. It's OK if it's a bit low, like 12V, but I wouldn't run the heater higher than 13V, as that would be likely to shorten the life of the tube.