It is the beginning of level 41 that is the problematic part. If possible, you might want to try focusing on clearing one side of the Doom Skull Bubbles first. It probably does not help you drop the big triangle of black bubbles alone, but helps your aiming a lot.
The Charm of Precision comes in really handy at this level. With over hundreds of games ahead, this is a good time to get it.
The Upper Video is from the BubbleWitchSaga Youtube channel, 3 Stars. :) Please subscribe!
This video is by Joge Skyghost Thanks to Jorge for the great video walkthrgough!