I done this mod a couple of months ago and it works really well.
It actually flies good unless it's pretty windy.
I tried flying in 14 - 15 mph winds to see how it would do but the wind would toss it around a little more than usual. Still manageable though, you just need to be prepared for the sudden bumps.
I don't use it to land on water, I have them there just in case the battery level drops faster than expected. I always land with about 20 - 25% battery left just to be on the safe side (over water or land).
I did place the I1 on water by hand to make sure it would float without getting near the camera and it does just fine. I used thin wall PVC tubes inside of the pool noodles to add rigidity.
It works pretty good with the gear up but you need to have the camera tilted downward a bit if you film with the camera other than straight ahead or straight aft. Most people have the camera tilted down anyway.
This mod gives me a little peace of mind while flying over water (even wide creeks).