I don't pluck anything but the mouth piece. And since I do a lot of hitters with pushed bowls, rather than restrictions I pop a lot of centered holes.

Heat where you want to pop a hole and puff just a bit. Then put just that tip in the flame and blow softly while spinning. Softly is the key word. The glass just gently moves out of the way and pops open. When I blow too hard or too fast, it pops a little unevenly.