Do you mean between the tank mount and frame ?
No, on the top of the tank. I didn't like the top of the tank sitting right up against the tub, but you might be able to slip some between the frame and tank. Mine fits very tight between the frame rails but it doesn't rub. The hanger seems to keep it centered pretty well. The hangers are just that, hangers, so you have to tighten it up pretty good to secure it and keep it from jiggling around. I also placed rubber straps between the hanger and the bottom of the tank. The rubber straps came off the stock tank hanger. I ground the pump and sending unit to the frame since it now sort of insulted.
You're lucky to be doing this without the body attached. That sucker was a bear to get up in there with the hoses clamped on. I couldn't see anyway to reach the hose clamps after the tank was installed, so I clamped them on really tight and set the tank at angle to start the hoses between the body and the frame. I jacked up the other side with a floor jack and laid on my back and used my legs and feet to push it up into place while I jacked it up. It fell off the jack a couple times and I cussed a bit. Not the most fun project I've ever done. When you're working by yourself you have to use what you've got. I hope I never have to remove it again, but I've done it couple times now so I have it down to a science. :-X