What is important for break power is cue momentum (cue mass x cue speed) at impact. Please read the entire optimal cue weight resource page. I think it answers all of your questions (and more).The problem with using a heavier cue is the acceleration would decrease, right?Whereas if the hand weight was added, the acceleration would remain roughly the same because no matter what, that weight will always be there in the stroke.
Regards,
Dave