This is an interesting question. I have ordered an ultrasonic 147(I am 90 kg) and a severne turbo 9.2 , and I am really wandering how much wind and chop this 147liter/93 cm board will take.
I will give you my opinion as soon as I have given it a try.
I have a kode 112 with an 8.0 severne ncx as my next sail. Maybe I need a smaller slalom board in between... like an isonic 107/117 ?