I would suggest a fin similar to the True Ames Convert http://www.trueames.com/wind_select....s_id=5&Convert
if you want to increase maneuverability. I use the True Ames Teardrop http://www.trueames.com/wind_select...._id=7&Teardrop
with my wave sails for general freeriding. The Teardrop is very similar to the MFC Liquid Pro http://www.mauifin.com/fin_info.php?id=23
Again, it doesn't matter what fin you use if you push the board too hard in turns it will slide out from under you. If you really want to push a board in swells then get the Kode.