The event "Unit - A unit Learns a skill" is used specifically for heroes, both for when they initially learn a skill and for when they train a higher level of an already learned skill.
The events "Unit - A unit Begins/Cancels/Finishes research" is used for units (usually buildings) that are researching upgrades such as Iron Forged Swords, Animal War Training, Defend, etc.
The events "Unit - A unit Begins/Cancels/Finishes an upgrade" is used for units (usually buildings) that are upgrading themselves to a higher level, such as a Town Hall upgrading to a Keep, or a Scout Tower upgrading to a Cannon Tower.
I don't think I'm dealing with quite the same pressures though, at the very least its a significantly smaller system. For the time being I'm just going to put together a quick scrubby box though and hope it works good enough to not make my house toxic
I do know this - xenforo dropped the ball by not keeping the vbulletin reputation comments as a feature. The loss of the Reputation comments data when we switched to Xenforo really was the death knell for the site when it came to all the users that left. I know I missed it so much and I got way less interested in the site when that feature was gone and I run the site.