If its the wataboard ex2 pro I haven`t used that one but it looks very comparable to the Zapata boards. It does have the option to rotate your feet individually which will make it a lot easier to spin tighter corkscrews and turn in general. It also has a locking option which will make it easy to learn to fly as independent foot control would probably make it more complicated to learn to fly. My board is one of the early zapata boards which does not have the option for independent foot movement. Looks like that one comes with a 45 foot hose with the option to get a 59 foot. I believe mine has a 62 foot hose and I wish it was longer, I`m kinda keeping an eye out for fire hose cause I wouldn`t mind a 100 footer. Not so much for the height, cause when you have 3' of air under the board it feels like 10' and if your up at 20' it feels like your on the top of the world. But more for the freedom of movement, as I like to stay as far from the boat as possible. It may not be as much of a thing if your using a ski to power it as the ski will tow behind you a lot easier than a 17' boat, but you sure can jerk a 17' boat around as you fall. I wouldn`t think that the longer hose would hurt on a lower hp pwc as it doesn`t take any power to have extra hose in the water, you just might not be able to stretch the hose out vertically.
Depending on where you are going to ride the quick connect steering adapter may be needed. With the standard setup the ski will be a floating pump to power the board, but the only way to move it will be to set the flyboarder down in the water and use them to drag the ski around. Looks like it will work fine to move the ski out a hundred yards from the launch, but it would suck if you wanted to ride a mile down to your favorite beach.
You do need someone who doesn`t mind holding the throttle on the ski very consistently. If its a old 90hp ski you may be able to just hold it WOT, but the more powerful the ski the more sensitive it will be. There are a couple companies that used to offer remote throttles for them and they are nice for experienced riders, but the newbs will need someone to run the throttle for them. Its a wholenother level of complexity to manage the throttle while flying especially if you are pushing it with something that has a lot of power. 200rpm difference on my boat can be 4-6 foot of difference in height.