Yeah, I was trying to figure out the best placement early on, and decided that the best pattern may actually be one with every other row offset to the center of the torches of the prior row, but I decided that I don't know enough about the calculations used to do a good job and I gave up. I tend to place my torches every 5 now, since I always have plenty.
I suppose if I really wanted to play with the study, I could use the mod in a single player world to try and design and test an optimal setup. If I ever find the time to get around to it, that is. Honestly, I don't know that I would install it if it were approved since I don't worry about fully lighting caves when exploring, and I stick to an overuse in my project.
I personally wouldn't have issues with others using it in any case since the only time that it gives any advantage is for people building to protect their works against creepers, and that would save me embarassment and re-build time if I am visiting their work and get it blown up.....which happened to me at the Spleef arena.....darn cats didn't even lift a paw to help keep the creeper back.
As for caving and exploring, no one is going to take the time and resources to light the entire area for a short pass through, and when travelling outside, I can pretty much tell when it has gotten dark enough for things to spawn without any help at all.