My Boss battles normally last no more than 2 minutes. I don't like leaving them setting around. I am now doing 3 to 5 per day between PC & VC Last night I was working on my 5th, I noticed I was not going to finish him before & ran ont of Stam. I was hitting 5 stam for 75 XP, meaning 15 XP/stam. When I switched to singles, I started getting between 15 & 23 per stam. This Allowed me to go up a level & regain my stam, finishing the battle in just over 9 min. This may help you go up faster. Good luck.
