For the longst time I had mine mounte on the windshield frame. The only problem what that with where they were I couldnt put my windshild down. But I never broke one and I could reach up while driving and adjust them as I needed.
Depends on the lights where I would mount them. Fogs or floods wide and low on the bumper (not hanging down), drivers mid heigth. Long range, mid heigth up to the roof. I actually had Long Range KC lights up on my roof rack but moved them down because of low pinion tree branches. They arent too effective on the bumper so I may change the lenses to make them floods.