This guide doesn't go into any detail about what you should be doing with excess Phoenix Flames between combustion cooldowns (or in short fights where you will never get a 2nd combustion), for instance, with the Phoenix Reborn trait.
What I've been trying to do is this:
Pyroblast immediately following a fireball when hotstreak is up
- If they both crit, do another fireball followed by pyroblast
- If neither crit, just cast more fireballs as filler
- If you end up with only a Heating Up! buff and...
- You are not in danger of capping Fire Blast charges, and have >= 1 Phoenix Flame charge...
Cast Phoenix Flames to convert Heating Up! into Hotstreak. Proceed as normal.
- You are in danger of capping Fire Blast charges, or you have 0 Phoenix Flame Charge...
Charge up a fireball, fire blast in the middle, pyroblast at the end
The problem I run into is that "Cast Phoenix Flames" step... sometimes the travel time of my previous fireball/pyroblast combo is so great that I either have to delay casting anything at all to determine if I can get a phoenix flames in, or start casting my next fireball the moment the GCD is ready, regardless of whether or not there's a heating up! available, and regardless of whether or not I'm in danger of capping Phoenix Flames charges...
What am I supposed to do in these cases? I can't fit Phoenix Flames in like I can fireblast, because it has travel time, is on the GCD, and when I want to cast it I don't necessarily know if I have a heating up! yet or not. It feels a little awkward and I feel like I've been losing some amount of DPS by holding my cast until I for sure know whether or not the pyro gave me a heating up.