David is a busy guy and not on here daily (some of us lack a life so we're here a lot...)
But I can tell you I have seen that exact set-up drive out of the back country on the bump stops without any problems. It wasn't David's truck, though it was set up the same. Another club member, the guy who did the thread on the long range tank install linked earlier, runs the same 265/65-18 BFGs on LR3 wheels (David has the Compos). Last year he had an air line fail while camping and we couldn't easily jury-rig around it so he drove it out. He reported no rubbing issues and was able to run highway speeds and easy trails - just not comfortably as the ride is awful on the bump stops.
I run a slightly bigger tire on my LR3, 275-65-18 Duratracs, and had to do some trimming to make it fit. I do get some rubbing when on the bump stops, though it is drivable if you have to. Luckily I haven't had to test it on the bumps on a trail.
I'm helping a friend do a set of LR3 wheels/spacer and 275/65-18 Cooper AT/3s on her LR4 this weekend. I expect to do some trimming, and I'll test it on the bumps to see how much rubbing there might be. Since each tire is a little different and we're dealing with mm here it will be close. I'm hoping she will have less rubbing on the bumps than I do since she's running spacers and a less aggressive tire even though it's theoretically the same size.