If you need 3/4oz to stay vertical, time to find a new place to fish. The big fish wont stay in that current, takes too much energy out of them. They will hang in the ends or sides of the currents. Use just enough weight to keep your jig down on the bottom. Doesnt have to be 100% vertical, but you dont want it way behind the boat either.
Like I said, I fish right below the dams here with 1/4 most of the time. I see guys fishing heavy jigs (1/2, 3/4, 1oz) all the time and they rarely even catch a fish. I assume its because the fish hitting the jig feels the weight and spits it long before they even feel it.
I’ve set my rod down with a 1/8 jig head before and came back to find it in the stomach of a walleye. Literally swallowed the whole jig head. I had to extract it later that evening