We regularly use fish flash's ganged up on the downrigger ball, then use a double stacker downrigger release above the ball, one clip on the cable, the other attached to a herring positioned above the gang of flashers. Been doing it for years. Beats the hell out of fighting small sivers with flashers on. All you end up with is a BB swivel between you and the fish.

It doesn't look as cool as the thing you showed, but it certainly produces.