Is there a way to have SilverDragon respond to chests more reliably?

For me, SilverDragon will catch maybe 1 out of 5 or 10.

The main reason is I'm trying to record coordinates so I can set waypoints in TomTom manually.

If SilverDragon could make the announcements, making the coordinates clickable hyperlinks, that would be extremely useful.

That way a chest can be pinned after it is removed from the map, by Blizard.

I'd need examples of chests it's not responding to. If they're chests with vignettes (i.e. they're on the minimap), it should be showing any ones which it thinks you're currently able to access.

If you want pure lists-of-vignettes, you might want to take a look at What's On The Map?.