I'm in Nth Qld & I would say forget about the lophs, they'll just rot in the tropics...it's too humid. If you want lophs...graft to trichs. Just keep in mind that if you graft & they get a lot of water they'll more then likely split from growing too quick. My trich's sat outside during the wet with no probs...just make sure the mix drains really well. I add a fair bit of perlite or coarse sand in my cactus mix (I prefer perlite). I would definately do as "gtarman" said & ditch the greenhouse...too humid. Because most of the rain up here is during summer it's not too bad, but if you had a wet winter I'd put them under cover for the duration Anyway, good luck with it...