I failed with both battery pull tabs, but I successfully used a microwaveable wheat bag in place of the iOpener, then carefully slid a store loyalty card under the battery. It took a bit of doing but I just took my time. The back of the battery was a bit bubbled but it still works fine.
My first time inside an iPhone. I slipped on some icy steps and bent my phone. Luckily it bent on the battery side and still worked except for the 'down' volume button. That wouldn't move because the housing was so deformed. Took my time and followed the guide carefully, it was absolutely fine. Took an hour and three quarters.