If you put a paddle hanging down from the beam, with an effort to be symmetrically
shaped on either side of the pivot, and then adjust zero as needed, either by filing your
paddle, or adding weights to the beam, you should be good. If the beam is aluminum,
then just adding a support for the magnet near the beam at level would be good.
You can put it on one end, no problem, but will need to add more weight to the pan
to zero. My RCBS has a copper tab on the outboard end, so it has significant correction
in the under-pan shot carrier, built that way.
An engineering prof had a demo device, looked just like a full sized axe at first glance,
but upon closer examination, the edge was not sharp at all. It hung from a hole at the
extreme end of the handle on a pin, very free pivot. At the bottom was a very large radar
magnet, an C" shape, opening in the C, up. Probably 4" diameter bar, tapered ends at top
to 1.5" diameter, tips had about a 1" wide gap that the head of the "axe" would swing
through. When it was just hanging there, the axe hung straight down, moved with no
noticable resistance. Lift the axe to horizontal (rotate it ninety degrees about pivot) and
release. Astoundingly, it did a dead stop before the whole head had passed through the
gap in the magnet after that fall, where it picked up a lot of velocity. Turns out the head
was copper, painted black, and the whole rig made to do exactly what it did - make enough
of an impression that this engineering student remembers the demo perfectly, and why it
worked over 45 years later. The eddy currents are proportional to velocity, so when the "axe head"
copper entered the very high magnetic field flux in the gap of the big radar magnet (probably
weighed 50 lbs or more) it damped it so heavily that it stopped before it moved the six inches
that the head was long. If swung from 10 of 15 degrees from straight down, it would swing through
a bit, stop on return, much lower velocity, so much lower damping. Heck of a cool physics demo,
IMO.
Bill