The problem is that your split line is projected from the center plane. In my boat the vertical angle of the boat side is changing towards the bow. So the sweep is going to be more narrow (lower vertically) in the bow. Since it's a rubber profile, it has to be the same height all the way.
I'd add a splitline and use it as your guide curve.
..although, personally, I'd offset the split face 0 and thicken and add the fillets..