Wind was going up and down, so did take the iS75. At some moments iS W44 was maybe better/faster? But a moment later the wind was dropping again. After some time I did try iS W44 and did make some runs on it. But not faster than iS75. Then the wind was to broad and the water was not that flat anymore. 

After some waiting, the wind was right-angled again and the water was nice and flat. Did go back on the water with iS75 again.

Fot me today the is75 was the best choice, I didn't want to walk back all the time. ;-)