Already had our day.
Only caught 4 shinys. It was, cold, raining and i stood under shelter for most of it with my little group. Did a couple of mewtwos during the event, one i missed the other had poor IV's.
It was not a fun event and Chikorita doesn't interest me much, i just did the event and went home. Meganium is not a good Pokemon so didn't care about IV's. Like you said, the real event is Metagross in a months time ;)
On the way home i caught a 100% machop, highlight of my day.