Is this still even possible to do? I did a post on this subject ages ago when patchwerk was the new cockblock boss however, all the information gathered in that thread is no longer useable. I'm trying to get my AB / scorch cycle going with CC on arcane missles however i'm missing most of the AM casts as I don't see the CC until too late

What I'm looking to do is cast spell x until i clearcast and then cast spell y... or at the very least stop casting spell x and not allow spell x to cast as long as clearcast is active