<div style="margin: 0cm 0cm 10pt">Since you have mentioned that you will not be racing and that you are a sport boater, then I would strongly suggest that you do not spend too much money on your set up.Simply get this package from Warehouse Hobbies with an M5 and be done with it for the best bang for your buck.Here is the link;
http://www.whhonline.com/product-p/builderspecial.htm</div><div style="margin: 0cm 0cm 10pt">Rudder behind the prop would be my choice for your application.No offset stinger to the right or right rudder set up. In other words - No muss no fuss set up.</div><div style="margin: 0cm 0cm 10pt">Racers turn right for two reasons;</div><div style="margin: 0cm 0cm 10pt">1st reason – Engine torque roll causes the boat to naturally lean or roll right (no brainer).</div><div style="margin: 0cm 0cm 10pt">2<sup>nd</sup> reason – Boat naturally will roll right so why fight the natural law of physics = Right rudder set-up which also buries the rudder deeper into the water for better right turns = clockwise racing.</div><div style="margin: 0cm 0cm 10pt">Personally, I would never use dual rudders unless I have a prop in front of each rudder and that one of the engine must also counter rotate to cancel the torque roll of the other engine.</div>