The biggest issue with front mounted antenna's is some LEO's may consider that obstructing your view.
Where to mount will depend on your comm needs. If your just talking about chatting with your 4x4 guys on the trail then mounting location is more of
where is easy/convenient to mount it. If you plan on using it for day/day on/offroad use then range is more of an issue and location will matter.
trail use comm only front will work, just take it off when your not using it. Put a 2-3" tube across the bumper and store the antennas in it when not in use.
for daily antenna then put 102" whip ball mounted on one of the quarter panels and the UHF GMRS antenna I would build up a bracket and mount it off the rear spare tire as high as I can get it.
