Fila sailing sessions

At the moment i do next to no dinghy sailing, so i try to compensate with models, my Fila goes to every pond with me, i am happy to do 8-9 hours on the water per week.
The boat performs well, but the jib needs replacement with a profiled one, fore more power in light air(at the moment all the sails are flat). Measuring the speed via iphone in the boat and using the runtastic app the boat sails at an average speed of 1.9-2 knots in 20minutes, sailing in the upper a-rigg range. This is very satisfying since the hull speed for f5g is some 2.1knots.
 Here are some pictures from our local pond:

The things to improve on the boat are:
-solving the cunningham issue, if it is tight the sail won't pop from side to side of the mast easily.
-profiled jib
-have to make a mould for the rudder, the boat is running a prototype rudder which has 40g =>heavy