Let us know how it goes. I didn't actually flower both sets of my clones to harvest, I only flowered the big ones (the 24/0 ones). The yield was great, but who knows, maybe 18/6 makes smaller and less-developed plants in veg and then they spring into mega-growth in flowering. That's not what the info says in the Bible, and since they were correct on the 24/0 versus 18/6 thing as far as I took it (e.g. through veg), I decided they were probably just plain right about the whole thing. Besides, while I did have two identical veg boxes at that time, I did not have two identical flowering cabs then. Ironically, I now have two identical flowering cabs, but only have one veg cab.
If you've got two identical veg *and* flower cabs, and a mother from which to take clones, that'd be the only realistic way to test the info in the Bible thoroughly. If I still had two veg cabs, I'd do it over again, and go all the way to harvest on both batches and see what the results are.
I suspect the 18/6 guy you saw just happened to have a good crop, and he decided that was because he did 18/6. That doesn't mean that's true, it just means he had a good crop and he *decided* it was true. But unless you do it in parallel to see the differences, a good crop, whether it's 24/0 or 18/6, proves nothing. I've had some great crops too, with 24/0, but that doesn't mean anything either. I mean, it's hard to say one method is better than the other unless you can compare the results with the results provided by the alternative method.
At least I was able to compare the results after a month of vegging, and the difference was pretty significant, probably 24-ish bud sites on the 24/0's, compared to maybe 15-18 on the 18/6's, something like that. About a third fewer bud sites and a third smaller, basically. If I'd been growing humans, one would have been six feet tall and the other would have been four feet tall. That was significant enough for me that I was (and still am) satisfied with 24/0 forever.