Hey there Cornish, I'm the druid that Juvencus linked to. I go up for every belt.
I've found that the best practice is to hit your wild charge when your toon is leaving your screen. Too early and you risk dropping back down to the pipe (or the abyss), too late and you won't make it all the way to the belt. This has only happened once to me, so I'd say that being too early is much more risky than being too late. Your results may vary due to latency/reaction time etc. Just try and be consistent with when you hit it, and then play with the timing.
I always let the belt pull me back. There isn't much point to being on the platform as A. you won't take damage on the belt and B. there's nothing in range to dps on the platform anyways.
If you have any other questions feel free to pm me.
Hopefully this can serve as a reference to those that are interesting in doing this job for your guild.
Here is the vid