for me, i can pull 10-15k on a boss fight. 10k if it's movement heavy, 15k if it's little to no movement with a LOT of crits to get a Pyro! proc and a good Combustion.
1.LB
2. Scorch debuff
3. Flame Orb (use when off CD)
4. Fireball spam
5.Mana Gem when 12-13k used
6. Evo when around 35-30%
7. Scorch Weave (1 fireball per 4-5 scorches) if running oom fast
8. Fireball spam when boss is @ 35% or less
9. Proffit
Well yea, obviously keep the buff up. Not sure why I didn't include that. You won't need to mix scorch/fb with good gear.