The one Rixa posted a few pages back is really worth reading.
From my experience playing the Deed v2 event, a TL;DR version would be: "Reach the last stage/map as soon as you can and, if your team can handle the very last free quest, farm it. Also, mind the emergency quests and the like, since they give points and either prysma or stamina/super stamina fruits".
And yes, Fever time lasts 3 minutes, and SSF extends the duration to 10 (it doesn't matter wether you consume it with 30 seconds left or with 2:30 minutes), as well as refilling your full AP. Also, fast-forward didn't help me while trying to make the best of my FT.
All the above is based on the latest jpCC tower event, so things might be a little different.