Earskins are fiddly in small sizes anyway, but septums are difficult. i wear 6g in mine, and usually end up taping it onto a taper and trying to unfurl it once its in my nose. i think i'd get horribly frustrated much smaller. i rarely take it out, and get to wear whatever jewellery i fancy. they're generally awesome all round
helix's are much easier cause you can actually get to them. and they're just sooo comfy! i could probably manage 8g?
couldn't get 6g cheap, not as squishy eyelets in my ears though. flare was too uncooperative, so i chopped it off
kaos eyelets would probably be easier, but i've yet to try small ones..