I love the Fusion, because it bonds well to glass. But from what I'm hearing here, sounds like a lot of things work well. Plus the fusion happens to have a very natural looking blue color.
Now, I didn't try to remove any of it though. I did mess up a couple of places, kind of, but as long as you fill in all of the space it looks fine from the front.
A couple of years ago I had painted the back of another smaller tank with a roller, that didn't look nearly as good. I also think the paint I used was a problem, but I believe spraying is definetly the way to go.