I used a 4" pipe hangers for the tanks, cutt off the ends, ground them down and then sprayed them with plasti-dip as well as putting the foam insulation on it. I plan on finishing them off with more plasti-dip just to cover the insulation. As far as the barrel holders I used a 1" metal strap cutt of the sides and then finished the same way.
The insulation was layed down to cover the screws securing the holders to the pvc...