It's also possible to do F3 - F2 - Flare - Transpose - repeat without any downtime, but I'm not too sure about the math on that one. I could imagine there being a breakpoint on mob amount where either 1xF2 or 2xF2 is better. Or maybe not. Too lazy to excel.

I don't think you could ever do five Flares in a row, anyway. Four was the highest with mana tick, Convert and pot. I guess there's technically Ballad, but you'd've needed two ticks of that to get enough mana back in the day, and even more now.