Well, I am a wing chun guy too; though, I can't say if I'm "good."
In my study of Bagua, I'm always comparing and contrasting the systems, and this is my takeaway on how to deal with YM-lineage WC using bagua tools: Hit or lift their root. Most WC guys I've met don't have a good understanding of their Yee Gee Kim Yueng Ma stance, or if they do, it's standing only and not in motion. They're all hands and no body.
Also, you can steal their forward to have them give you the outside edge. I know you've expressed that it was hard to get there, that's why they've got to give it to you. Most YM guys I played with are good at re-orienting that center quickly, so if you keep trying to round the corner without them giving you a reason, you'll never get there.
And, if someone is backing up quickly, isn't that what long range kicks are for?
Please take what I'm saying with a grain of salt, I'm no expert, My bagua studies have been less than a year. WC for about 4 years.
Cab Driver: "Are you ok?"
Jackie Chan: "NO!"