Hey Bruce
As long as you've brought this thread back to the front, let me suggest that a couple of strong rare earth magnets attached (just stuck on) on opposite legs of the horseshoe ("U") shaped magnet, should boost your power output noticeably without actually altering the original unit in any way.
This still qualifies as a really amazing deal, and I'm still shaking my head over it .... but it couldn't have gone to a better person, and I'm delighted that you have shared it with us all so well !