We troll smelt as well and use otters with single keels. I believe that the slack in the tow line leads to more hits. The boards are constantly speeding up and slowing down, you just can't have them out to far. Good luck!!!
I remember a post from the past about a ball snubber with little water resistance. Can't seem to find that post, any help would be appreciated. I'm currently using the Amish outfitters version. Thanks, Matt