you really have to plan this out. the streams always fire in the same arc. you can't change that. what you CAN change is where the busters stand. best thing to do is figure out the ghost's pattern before you lock in where the first GB stands. Once you get that going, drop the trap, lock in the first buster, then the second. wait for the right time to fire the streams and catch him between them, open the trap… bam, done.
OR you can just try to time things right, set up the busters anywhere you feel and wait for the ghost to fly over the trap and just suck him in without the streams.
I do that when the damn ghost doesn't want to fly low enough to be caught in the streams