It's weird that the other bowls didn't leak before but perhaps they weren't getting enough fuel due to the leak at the fuel supply T. So, having had enough of putting carbs on bikes, finding leaks, pulling them, fixing and repeating the process, I made this:
Time to find some bowl gaskets and try again. I did replace the petcock with one a scored from Amazon, it's like it was made for it, which it was!
In happier news, I did use some starting fluid and get to hear the bike fire up. That exhaust is mighty loud and raspy. Sounds good though.