With my #47 recurve I use 2018@30" +125gr pile or 2114 at 29" The reason? They just fly better than any other combo I have tried. What kind of fletching are you using? I have 5" shields and adjust the nock to get good clearance. Fishtailing usuallt occurs when the fletch clearance is off. Or the nock is leaving the string to one side. ( torqueing the string.) Also try a matchstick on the arrow rest thereby giving minimal arrow contact with the rest.