I can only say mount them as temporary as possible so you can move them around.
I have one in each front wheel well above the shock hoops, in the rear i have one mounted on the t-case crossmember pointing to the diff and another at the back center of the bed pointing to the back of the diff.
the only thing i dont like is the fronts don't light up the trail in front of me very well so i have to use my head lights and that blinds the guy in front of me, so I am always turning them off.
Rick