When I lead Overland Groups I try to cap it no more than 7. Minimum 2 if you're going where it will take more than a day to walk out. Steens Mts. in Eastern Oregon for example, you can get to spots where you're the only human for miles. (More cows, antelope than people)
The other key question is having similarly built trucks. 3 overlanders with modern engines, 35" tires etc. are going to be waiting for that guy in the early 70's a cool but slow classic on 31's.
This was just over a month ago in JUNE in the Stens. It was over 90* out in the valley, but snowing in the hills. We had 5 trucks, it was a nice balance. One had no lift and no armor, guess who slowed down the speed of travel. Only an issue when you have waypoints you want to hit, or a known camp that would be great to stay at.
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