Your mix sounds good, your light poor (more later) and your wintering...maybe. For light, particularly if you have other tropicals anyhow, you couldn't give it too much light if you hung a 4' wide fluorescent fixture with 'full spectrum' T5 bulbs 5-6" above it for 15 hours a day (on a cheap little timer). They're also great for Ficus, and most other sun loving trees. For just one plant, you can find those new spiral fluorescents in as high a wattage as possible, turning the pot daily, but it won't be as effective. Don't forget olives are Meditarranean and used to growing in hot, dry weather for months on end. Water only when most of the mix is dry, but as that's fast draining, you can do it more often than you'd do in potting soil, and don't let it sit in drain water. I'm not sure zone 7's warm enough for it to do well outside - it really needs to stay above freezing (40-45 F.) at any time, tho' in Oct. thru Dec., water less often and let it rest a bit.

Lucy,
Thanks for your incredibly quick reply. I'm sorry, I should have added that I was told this is a Florida "black olive" with tiny leaves that doesn't really have any edible olives, just little seeds. It grows mainly in Florida and the Caribbean(I think) and likes heat and humidity. This will be the biggest challenge in Asheville, which has a nice warm climate (not the heat of the Deep South) but the air is fairly dry.
So the low humidity is going to be a problem. As to heat, we are already in the high 60's to low 70's with nights in the 40's and 50's - i.e. nice in the day but too chilly at night for any of my trees.
Have I just answered all my own questions? But what about plant food? Any special needs, or is the "blue stuff" from Miracle Grow enough?
Back to the lovely air in Asheville: my tropicals have stopped making aerial roots since we moved here but last year I was able to force a fine crop of them on my old Schefflera by using spagnum moss and plastic wrap.
Krys

You're right about the type of plant (it's Not an 'Olea Europaea) but care is not much different. Any well balanced house plant fertilizer will do, not necessarily high (low pH) in acid though.

Lucy,
Thank you for your help. I think it'll work. I'll look for the fluorescent bulb. I'll post a picture to the gallery later and let you know.
Krys