YOu can get those nylon fan ties that slide through the radiator with locking clips. THere pretty sturdy. As far as the brackets go, I dont know. I havent bought one myself yet.
Yes the Nylon fan ties would work. I myself used heavy duty zip ties. It's very solid. As for the brackets I do not know as I used heavy duty zip ties for the entire project.
It is held on great with the zip ties and the overflow bottle/bracket.
mine has some zip ties, and my dad made a little bracket kind of thing that hold the bottom of the fan from moving. But i would say zip ties is the way to go.