Jud:
Actually, from what I've seen around Phoenix, I don't think many of the newer courses there push the envelope of the 90 acre limit on turf ... I think most of them are down around 75 acres, saving a lot of turf for a huge practice facility and maybe for grass around the clubhouse! But, you are right, there is no such rule in Mexico that I'm aware of, and we tend to build our courses wider than most people. I am not sure of the total irrigated area at Bahia de los Suenos, I never heard a final number from them.
That approach to #6 is tough because it's uphill even more than it looks ... without bunkers next to the green, it's difficult to judge. We thought about having some mowed rough up close to the green so a shot that just missed wouldn't come way back down the hill, but were not sure what the paspalum would play like at that height, so they are still mowing it all short for now. Someday I hope to get back and do some fine-tuning like that.