For other users that may have similar questions: the only guidance is not having them right under the upper radio. Typically you try to criss cross them so the radios are furthest apart when under another. For example of a 3 radio stack the top will point to the NW, the middle will point N and the bottom will point NE. I know that is rough angles to make the point, but it's common practice. Also, if you have the vertical space, giving them a foot or 2 between horns on a vertical stack should help.
You also always have the ability to not mount the GPS puck in the adapter, but I know bein