To sync your data with your watch you have to open the mobile app once or reboot your phone (so that the activity is called).
I've tested it on my LG G Watch and it's working but for now I haven't tested it in english, just in french so if there are problems in english just tell me.
The limits I've set is 50 events and 2 months max, but maybe later I will make a setting so that everyone can choose it.
That's it, test it, share it and give some feedback.
here are some screenshots, tell me how I could make it look better