So let’s take a closer look at the case. If we have an 8 meter spar of 20 kgs and suppose that they are evenly distributed that means the centre of gravity at 4 m it would give us a righting moment of about 80kgm.
You make a modelling error. IF the above assumption is true then you would also have AT LEAST 10 kg of tipweight which we know you don't. Even if the mast is 8.5 mtr as the F16 mast are then the tipweight would still be at least be 9.4 kg.
In fact the tipweight is all we need to make the righting calculations.
The minimum tip weight for the F16 carbon mast is 6.00 kg, the Superwings are in the range of 8.0-8.5 kg (Valtierri's is the heaviest I know of so far. This means that the difference in righting weight between the carbon guy and the aly guy is (8.5-6.0)*8.5 = 21.25 kg.
If we assume that 85 kg will do the job in all conditions then the carbon guy (of equal body length)needs to be at least 64 kg to right his boat and not 40 kg or something. In this crude mathematical theory that is as we have just totally ignored the weight of the stays + ails and the fact that water is clining to them. In fact the difference in reality will be less. Even more so when the sail is still curved and pulling the rig downwards because of the little wind that still flow across it. In fact the weight of the mast is not all the weight/force that needs to be lifted, it is only part of it.
The naked spar should not be more than 15 kgs if you sail High Performance
The difference is not that much for sailing itself, it is indeed for righting. However I do agree that the F16 alu mast should be about 15 kg for the bare section. The only way to achieve that is to have a new die made. So if everybody will become a paying member of the F16 class then we may well buy a new die as a class and solve this issue.
Wouter
