It would be your best bet to simply go back to your piercer once your piercing has healed, and let them estimate what the best size for you is.
I’m not sure, I guess circular barbells just not used as initial piercing jewellery because thing could catch on both end balls, and you might have even more of a chance of it twisting about than with a CBR. The most popular initial piercing jewellery is the straight barbell, simply because it reduces the risk of those things happening.
You know, I think it’s entirely up to personal preference.
You can always think to yourself, do I touch my ears often, do I wear large headphones a lot, is it the side I sleep on, etc. Those things could mean having a ring in your conch is annoying.
But you could always try it, have a ring put in by your piercer, and when you don’t like it, switch back to a post with a nice treaded end.
That’s a question better asked to the APP’s Safe Piercing people.
That said, DO NOT PIERCE YOURSELF.
You’d better ask the professionals over at the APP Safe Piercing blog.
If I were you, I’d direct very specific questions regarding healing time to the experts over at APP’s Safe Piercing tumblr.
You should start with the piercing you like best. There’s no real need to “test the waters”, the healing process should be the same for pretty much all cartilage ear piercings, just as the type of pain you’d have to expect.
I’ve seen some piercing shops who also have a webshop, but it’s a rarity.
If you can, buy Anatometal and Industrial Strength (and other quality manufacturers) through a physical piercing shop. Both manufacturers have a directory with the shops that carry their jewellery (here and here).
That being said, some people don’t live anywhere near a reputable shop. I, for one, know of only bad to mediocre shops with sub-par supplies (EXTERNALLY THREADED, UGH), and the one good shop within a three hour train journey has suddenly upped sticks and left. The only other shops I know to carry good stuff are in the next bleedin’ country.
So, I’ve got to resort to ordering online, too. Your best bet would be bodyartforms.com as they deal pretty much directly with the manufacturers, and they can order custom pieces for you (please keep in mind that those take longer, as they’re made especially). The only downside to their shop, is that they still stock acrylic, and it would be better if people were stopped from putting such toxic waste in their ears.