My guild locks used to have a policy of just getting 1 sbolt and 1 SP off on adds, then swapping back to curator to DPS, regardless of the status of the flare. You don't want your locks trying to get KB's on flares, b/c of the opportunity cost of casting that ONE last spell, and having the mob die before it lands... the DPS hit in that case is just dumb. Let your melee kill the damn things. The dot strategy previously mentioned was basically how we used to approach CoT: BM adds when we were all undergeared and leveling - you know they have X HP, and you know how much damage your dots can do... so apply those dots and move on.
As our DPS has improved (and our raid comp changed as we go) we've taken to just leaving the locks on Curator 100% of the time. Just as a friendly reminder: time your Dooms to hit at the *end* of evocation so you've got a better chance (with 3 warlocks nuking) that ISB will be up for when the CoD's proc. With that many warlocks eating ISB charges though, you're all going to have to be aware that if ISB is up with 3-4 sec till doom goes off - NO MORE SHADOW BOLTS
It will also help to issue a friendly reminder to your shadow priests that while their 4K SW

's are cute (or whatever they do to eat ISB charges), all they're doing is lowering raid DPS and making the boss stay alive longer. Back when I was 0 21 40 and running w/ a shadow priest, my ISB charges would get eaten up *really* fast, until I realized he was saving his MB and SW

for when the proc was up just to see some big numbers.