I played with it some. I was running it at B+ of 300V so something like 280V on plate and G2. 3.5k or 5k (better) load. It did not blow up, and measured pretty well. I did not build it into a complete amp, just a breadboard experiment.
In general I think people are paranoid about the G2 ratings on these RF tubes. In general you can get away with higher voltages in audio use, especially in triode mode. UL maybe not quite as much, but you can definitely push it over what they specified.
Also look at the DH variations of the 6146 (like the 8042), they have a lot of potential as well.
Pete