Watch out, the Fu93 has a tail width of 40.6 while the IS87 has only 36.6. Just take a look at the specs on this web site. The Fu101 has a tail width of 42.7. Of course, it's not only the width that counts, but also the tail thickness and the cutouts. Wave boards have often pintails or swallow tails and are very thin (small thickness) which make them much easier to go through the chop.
About the Kode, yesterday there was a guy with a similar type of board. He smoked me almost every time. He was faster because he had more control. This has also to do with technique of course
I think that in heavy chop, the Kode will be faster for most of us "simple mortals" compared with the Isonic, just because of the better control in heavy chop.
Grevelingendam can also become very choppy with strong winds from the West to North.
In 21+ choppy conditions I'm on a AHD rebound (FSW) board of 83L with 5.5, 4.7, 4.0 wave sails (NP Combat), having the fun of my life. I'm 87kg. I don't like the Kode, because of the US box. I prefer the powerbox.