The fish I have caught on the surface in Lago Strobel (Jurassic) take big foam flies just sitting on the water or bobbing in the waves. I don't know that they are eating anything natural. I am not sure there is much there other than scuds and snails. I think when the conditions are right they just check out what they see floating. I have caught them on mice or Chernobyls and similar flies. Bigger is better since when the water is rocking and rolling you can't see the fly. I have been tying with large clumps of congo hair. I like the look of the Gypsy King. Thanks!