The "swivel" rig you described is a nice rig to use especially in heavy current with a 4-10 ounce lead ball attached to the bottom of the rig (dropper). It is very similar to hand-lining/downrigging but you are holding the rod.

I especially like this rig when trolling over irregular bottoms and it allows you to "contour fish" inside the ditches/wash-outs along the river bottom where the muskies will be laying to elude heavy current.