Isolation only makes things quieter, it doesn't eliminate outside sound. Nothing you put in your ears can ensure complete silence, except maybe a screwdriver (don't do that).
You should be able to hear your fingers rubbing no matter what -- as long as you're paying close enough attention. The character of isolation I get from custom IEMs and universal IEMs is different, and can take some getting used. Also, your customs need some time to settle into your ears when you first insert them, so as long as they're well-positioned when you first put them in they'll settle in better if you fuss with them less.