I was playing the local BoP last night when a buddy of mine showed me that it's possible to shoot the 25K/50K/100K loop between the rocket ramp and the heartbeat ramp over and over again. It's easier with a dead flipper pass to the right flipper after it loops back at you but it's totally possible to backhand as well.
So, naturally I played a number of games doing nothing but practicing this shot over and over to determine exactly how many extra balls you can light with this technique. I managed to light all four of the extra ball lights but I couldn't manage to ever light more than that without draining or collecting one.
Thus, I'm curious if any of you have tried this technique. Indeed, I wonder if they can be stacked up indefinitely. That is, if one of the EB lights can be "lit" twice. It seems like you can get unlimited extra balls this way. You have to let the loop combo time out to start a new one after you get tired of the 500K/shot.