Just thought I'd share in case anyone is attempting the same feat.
I had to use the nipple shield since day 1 at the hospital (although I am becoming increasingly suspicious of how neccessary it really was) and it was driving me nuts. Having to get up out of bed a bajillion times a night to wet the stupid thing was driving me BSC...not to mention how many times I lost it at just the "perfect" moment (like when DD decided to start screaming at 2 a.m.). So, two days ago I put the shield on, allowed her to nurse for about 5 minutes, unlatched her, removed it, and tried the bare nipple...it took a few tries but she finally latched! I think the shield may have molded my nipple into a less inverted shape and that's all it took! She's been nursing on both sides without it ever since!
So, totally worth a try if you're looking to drop the stupid plastic pain-in-the ass...hopefully this helps someone!