Sorry - I'd have offered to begin with but my fishing buddy (the boat owner) is in Canada, hunting bear. I'm in need of a lift myself for the next few weeks.
From what you've written, you're making the same basic choices I would have made. I think our crucial need for next season is down speed and temp - we just can't dial in a presentation if I don't know both. The currents have been severe this year and I don't have enough time on the water to estimate speed by rigger cable angle or dipsy rod bend.
Just guessing - experiment with your speed, direction and depths. I've seen regular reports of guys running anywhere between 2.0 and 4.0 mph gps speed to get a lure speed of about 2.5 - all depends on the current at that moment. That king hit after you reversed heading, which presumably changed your speed, also affecting your depth. Too many variables already - I'd have left the presentation alone without another hit or two. Did you turn and retrace your path (both directions) after you went back to no action?