A new c:geo tip to add to Team Sydnes' list of recently discovered tips and tricks: If you solve a puzzle and put the solution in the personal notes on the cache page, C:geo helpfully includes it for you when you pull up the cache info on your phone. This has made our puzzle cache hunts MUCH easier! Happy caching!
That reminds me, have you noticed the new pencil icon (called "corrected" coordinates) near the listed coords on mystery caches? You can change the posted coords right on the cache page and the "new" coords will download in the gpx file. Those coords are only seen by you.