Taipan 4.9 is 107 kg but has little hull volume and small beams. Whilst the boat can be fitted out with a kite, the boat was never designed for it. Viper is designed for the kite and its associated extra loads, has greater hull volume, more robust beams and more structural rigidity. It is also built with minimum exotics to keep the cost down which is important.

What are current F16s weighing in at..... 110 to 115 kg. Why not build a boat with a little extra weight to allow ease of building to min weight and add a small amount of corrector weights that can balance out variations and be removed as the boat gets heavier.
If the class would like to take the next step increasing their fleet numbers, then they will have to make it attractive for the larger catamaran manufactures such as Nacra and Hobie. If they stick with their hard nose attitude towards super light boats using exotics, then it will stay a very small class.
I would not be surprised if in the future we see an F16 ‘manufactures’ class get off the ground, supported by major manufactures and the current F16 class will soon become like the F18HT is to the F18 class.