Hey big dog, welcome to the family.
It is very important to securely mount the tanks while at the same time brace the gunwale so it wont bounce on the top of the tank, it will crack the filler neck (seen it hundreds of times), I assume your tanks are like 8" in diameter (if your tanks hold 10 gal and are 48" long that would make roughly 8-8 1/2" around), the coolest way to make some badass brackets would be to go to a metal recyclers and see if they have some 8", 3/16" wall aluminum pipe and get a short length (like 10" or so) and have someone (or yourself) build you some, they're pretty simple to make and would be bullet proof, all you really need is the time and knowhow, hit up CJ222, I think this is right up his area of expertise...
I have a set of tanks for sale with the brackets, but I can't separate them, $250 for all, but probably not the way you want to go...
edit; most of them mount throught the bottomm of the hull though...the last one I did the tanks literally hung from the deck and rested in some wood blocks cut to the curvature of the bottom of the tank mount, it was a real bitch, but came out really clean, the guy I did it for was totally stoked because you could not tell how they were held in.
GT
