Well, actually, squeezing in 6 is feasible with enough Spell Speed, so the ideal would probably be:
R2 (Swift + DWT), R3 (3D + F), R3 x5, DF ... F ... F = 2770
I'm not sure what "enough" Spell Speed is, though. At 856 I'm cutting it kinda close.
https://www.youtube.com/watch?v=TuJnEu9vlQY