Normally i refuse to response here anymore but i will do now because i hate to see this weight thing again happening.
The fact is that the best sailors are at the Vipers at the moment. When you put Ashby on a 10 kg heavier A-cat ( what type ever)he will probably win because he is the best sailor out there in A-cat. When you are going to put JC on a F16 of 110 kg or less he will probably win because the boat will react quicker and better and he is a very good sailor.
At the moment the Viper is having the best sailors on and then you have the biggest change of winning.
In F18 the minimum is 180 kg and when you have a boat of 200kg with a top sailor who is winning the events will the class than raise the minimum to 200kg. Likely not.

Why is the weight issue of F16 everytime coming back, the class rule is clear on what can be done.

I really do not see the point why F16 is used everytime to discuss his minimum class weight.
It is very frustrating to see this weight crap happening everytime, go sailing and develop the class