thanks on your comments.
Above 20knots I have Futura 133, but this conditions are rera so mostly I will use iS150.
Ok I have now some guide info, and for now I will stay like below:
RSS 7,8 > 48 Tutle stock fin
RSS 9,5 > 56 DeepTutle stock fin
> + I will buy 1x new ~68cm fin for Low wind