somewhere on here is a post by dave on how to post pics... just do a search on his name and look at his threads. (he rocks.
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as i have killed one onc and have another one sickly and only managed to grow two fairly well, i'm not a good person to give advice on them, but as i recall they can handle a fair amount of light, and i think at your latitude you're probably not going to fry them. mine get morning light and at least 2 of them (howeara and a vuylstekeara) seem happy.
rocks are good as they don't break down and encourage rot. i have my two dens in them. just be sure to water and fertilize (judiciously on the fert.) the water is going to run right through and that's fine; for a four inch pot you may want to water 2x week. that pouch looking thing is a pseudo bulb, and it's where the plant stores water. once it gets wrinkly it won't plump back up, but that's ok, it will still get along fine.
i'm sure the onc folks will weigh in at some point...