Like I said, you could filter out Pyroblast crits from your normal dmg out scroll area, and leave the rest in.
The way mine is set up, if I see HU or Pyro! with no Wham! noise, then i know its only FB crits. If I see HU and/or Pyro! with the noise, then I know I'm building a better ignite. I can also almost get through an AT/PoM macro just by audio cue alone knowing how many pyro's crit and how good my ignite is. I still check MyBigIgnite meter, but its helpful for tempo.
Glad I could help though! Keep messing about with it when you get the time. It really is a properly powerful addon. I've started to make plans to couple MSBT and TellMeWhen into set areas so I can have the numbers and my TMW indicators together in their proper spots while using conditions for both to indicate probable next action in a more clear way.