Sailing a 125 and 152 litre board - feels like a different sport compared to sub 100 litre boards.
Not saying big boards like a 125 lite are not fun but in 18 knots at 75kgs a much smaller board will be much more fun.
Interesting that Chis Adamson, who lets face it can sail a bit

his biggest board is a 106 Tabou Manta and he is around 82kgs.
He has slalom boards in the same brand all the way down to 40 odd cm needles using tiny fins.