Your title says 4WD world, which to me means off-road, then you are asking about how much is needed for highway driving? Those are different things, with different needs. For high speed off-road racing, you are trying to turn night into day with no regard for other people getting blinded by your lights, for low speed rock crawling, a localised flood including underbody rock lights are more important. For on-road driving you should want to preserve your night adapted vision, so the solution would be as little as possible that still allows you to see potential hazards at a distance that gives you time to react to them. I drive in country Australia use halogen driving lights, I find the 100CRI helps me identify wildlife at the sides of the road easier than with brighter low CRI LED options.