Garmin Edge 810 Data with Garmin Virb

I can't get my Edge800 data to align properly with my Virb basic video. I've got a point where I'm stopped at a red light. I aligned the two so that the overlay starts accelerating just a fraction of a second before the video shows me moving off, that was as close as I could get it. But less than 30 seconds later I have to brake hard because a car stops in front of me and it takes the data overlay at least 4 seconds to reflect that.

There are then similar problems with gradient info a couple of minutes later with it changing very late (or not at all in one case) but those are very short hills so that's less surprising.

The video is recorded at 720p/60 and I imported the fit file from the Edge.

This is the first time I've tried this so maybe I'm doing something wrong? I also found that when trying to tweak the timesync on the gps sometimes it would just ignore my changes. I'd change from (say) 9:24:28 to 9:24:32, click Done and when I went back into Adjust again, it would be back at 9:24:28.

(I don't do 9 hour rides, that's just how it works on the Edge if you stop the timer when you get to work and restart it when you leave without resetting it. I've just noticed I can actually scrub on the gps adjust to any point in time when the Edge was switched off.)

oh my bad. that was easy to do. :)