im not sure what is better, i ended up doing different starts with delaying / using dos situationally without bc varying on fight and situation.
(some encounters , like aluriel where u get "blown away from frost adds", u can root your self with it) but i often had to delay avatar and dos for bc, or dont use bc for ages to be able to get it synced with draught of souls. the problem: if u delay it once, u have to delay it next time too and so on, or u say fuck it, use draught independenantly and it will start to sync better on the 3rd time.
but generally: u always want to use draught within avatar. never without. And you dont want to delay avatar at all. and you need fucking bc within avatar. And u want draught in this window everytime. (and u need to have the cs debuff on target).
Convergence fixed those "fuck it" scenarios pretty nicely for me.