I fished Dolphin for about 3 years, on and off, and I had the best luck at the south end of that trolling pattern. You'll find the boats in about 100-120' and see where the "corridor" is, with boats trolling in a north/south pattern (obviously). My hot spot is when you get to the south end, especially on the incoming tide, turn west and do a big loop after you pass Dolphin Pt. I troll just herring on the downrigger,
and had good luck hooking the 6-14 lb range in this turn. I stay within 20' of the bottom, give or take. It's an easy troll with pretty consistent bottom contour, but around the inside of the point it varies. I would just leave the downrigger set where it was, do my 300' loop, and get back in the track.
I have not seen many hook-ups north of the ferry lane, and contrary to popular belief, THE FERRY HAS THE LEGAL PASSAGE RIGHT OF WAY and they use it agressively. You'll not see them slow down for gear (those w/o downriggers) and they will fly 20 yards off your tail, so save yourself some stress and stay south.
Good luck out there.