Eric I belive Cabela's has weights that are universal that are bent so that they can swing away from your boat A friend That fishes Lake Ontario with 4 riggers off a 19 footer says they work realy good.Go to cabela's then to fishing then to Trolling gear,then downrigger weights then to Cabela's Directional Downrigger Weights.You can also use the pancake weight but you have to modify them.I hope this helps.I don't think I have ever seen the fish weights that you can do that to I would be interested if you find a place that does that.
I realized this would not get you out like a planer, but I was wondering if you could just get it the fish. to track a little outside the prop wash / cavitation it might get into "quieter" water as far as the salmon are concerned. I think Fishlessman or Adrien mentioned actually looking down and being able see fish spooked right under the boat, so maybe its a game of inches? My fish weights have bendable tails; I had not tried and was wondering if anyone had...
Planers are my next big boat project...got to get a mast and the whole 9 yards...And a heater like John S.