I've found that double flares can vary a lot in both the flare size and even the gauge accuracy, depending on the material... organics tend to vary a lot more than say glass.
I was having a lot of trouble with df plugs for a month or so ago, but I've been at 2g for over a year, and my problem was that I had been sleeping with nekkid lobes, and then I'd put in a sf plug earlier in the day, then think I could switch to a df easily in the evening. That resulted in my right lobe getting pissy for a bit.
Lay off for a while if your lobes are getting irritated with the df attempts, and then I'd say wear your largest (you can tell visually as well as if they fit tighter) sf plugs for a bit, or you can try wearing heavier hanging stuff, if you have it. Or as someone else suggested, try stretching to a 1g for a while, then downsize and you shouldn't have any trouble. And sometimes you have to push a bit to get a df plug in... just so long as your lobe doesn't get traumatized to the point of being irritated, you're good.