I've had a couple weeks worth of experience
I'm along for the ride on this one. I have 2 semilarvatus in a 55g QT right now. Both fish are around 3" in size. I let them hang together for a week but the alpha won't let the other one eat. I split the tank with an eggcrate tank divider. They are both eating now and check each other out through the eggcrate. They'll be in there for at least 5 more weeks, I'm hoping they'll get used to seeing each other and chill out.
If they never pair up, I'm hoping the 360g is going to give them enough space to steer clear of each other, at least until they get larger.