Couple of things.
First off, I had the land version of the same plane. Nice flying plane. I powered mine with an OS .15 LA, and it was a perfect match. My brother has one that is powered by a little Hornet, I believe (.09?)
Anyway, he can flat spin his--and it's a very nice flat spin, so these are very capable planes. however, Just a word of caution, don't fly it on windy days. 5 mph is about max. If for no other reason, the small engine will have trouble making any headway upwind. Also, the wind will throw it around pretty good. They are easy to hand launch. If I were you, and I wanted to fly it without the hassle of water, I would hand launch it, and then belly land it in the grass. Just make sure the motor is not running when you belly land. Of course, flying off of water is good, I'm just talking about another option you might want to explore. Especially at first when breaking in your engine. Dead sticks can be interesting when there is 50 or more feet of water between you and your model, and the wind is blowing OUT!

Anyway, on to the "stickers." You don't need stickers, you need to start putting trim colors on it. That is way too much white, and you will definitely have a hard time with orientation. Start adding covering over the white that will accent the plane, while still allowing you to tell up from down, and so on.

BTW,
I built mine with two left wing halves. You are definitely correct about the "plans." There really aren't any plans, just instructions that are apparently not written for beginners. My two left wing halves were sanded until they fit "OK," and then I covered and flew it. It flew like a champ--that's how honest these planes are! I sold mine because it didn't do what I wanted it to do (I was hoping I could fly it on my 3 acres, but it was too fast). Still, it flew great! Those ailerons won't move very far at all, but trust me--they'll make the plane roll just fine!

Good luck with it!