I'll never take mounting a tank lightly, with metal bands or rivets. Bands break and studs not mounted in the standard way will crack at the base and leak gas, "Dangerous"! Braze some brackets on that fit the frame. Lose those studs (grind em' flat) and braze over them. You could make brackets like mine and then put one straight stock under your top tubes up front and drill through that and the plate at the back, then put bolts through it, "Solid Man"! You can buy a torch cheap at the hardware store, it comes with instructions. Get some wielder goggles and a way to hold the tank and brackets without getting burnt. Wash out the tank first with a degreaser like "Super Clean" first.
Best thing I ever did, zero tank problems!
You got a cool bike, it's gonna look dope!!