If you have 4/4 diabolic its worth using 2/4 t19 and drop lessons out. Maybe titanforged hc gear eventually pull ahead of ur t19 pieces but not much then again you miss the cast time reduction for sure. Prydaz is very viable now when mastery is equally good with haste and crit. I use it with feretory.
And now sc pull ahead of channel demonfire. It sims higher and has no room for error like cdf.