Ali, two 120 class turbines will be fine. Michael Wurm has been using P-80's but vertical maneuvers are mushy. As Billy said with proper equipment layout you should not need nose weight. I would not contemplate using the dummy fans for anything other than static. They will affect the intake airflow, and can break loose. have been flying with an extra 2 liter tank which was mounted center between the saddle tanks. This gives around 11 minutes of flight with some go around time. At around 64 lbs wet, there are really no issues with a plane of this size.
Mike