ok - heres a possible solution for Bino's of diff weight, Drill a series of holes in that arm under the bino's. That way if other binos weigh less just move the weight up the arm (which i gather is there for counterbalance) similar in action like those balance scales with sliding weights.
That main weight looks like its adjustable anyways, but if other binos are lighter and the weight can't move any closer, you will have to move the pivot point closer to the weight, that way you will have a bit more of adjustablilty
ps comment on RAJAH235's post - maybe some Flashing Red Leds
(flogged of a pushbike mebbe, just joking ;-) - unless you own the bike )