Have a look at an antenna with a gain of between 4db-6.6db, any higher db gain and you're "flattening" out the path of the transmitted signal too much and anything below 4db is too much of a "spherical" radiated pattern to achieve a good balance.
I'm running a GME AE4705G on the rear of my JKUR. I mounted it to the swing away on the tyre carrier.
It was formally mounted to the front of the car and never had any problems with it and now being on the rear it's not in the way of pics and vids and as I'm a trip leader with MJOC I'm leading convoys I'm in 95% of the time.