I also have a GATO and looked at all the ways some folks tried to attach their tower and I decided on this approach (see attached drawing). I went down to a hardware store and searched in the nuts & bolts section and found things that, at least had, a rod like section with a ball on the bottom and then looked around for rubber grommets that the plastic ball would fit in. I also sanded down the ball so that it would fit into the rubber grommet somewhat snugly. I mounted the rubber grommets into the hull portion on the sub and glued the plastic pieces with "Fast glue" at each end of the tower section. If the tower section would get hit by something, it would just move a little and not break something. It also allowed for detaching as I have running lights as well as a Hi res camera mounted in the tower section. I hope my drawing gives you a somewhat picture of what I was trying to convey. Best of luck with your project.