Easy Tagging on the phone to create XML.

Hello,
We are shooting long (over 9 hours) sports events live with a team of 6, mostly with Panasonic GH cameras.
I would like to edit Race Recaps efficiently after the race, from the recorded shots of each camera, at the end of the live, with Final Cut Pro X.
I am looking for a way for very cameraman to create XML on the field while shooting, from his phone, or smartwatch.
- Every time there is a race event, a very beautiful shot etc, i'd like him to just click somewhere to "save" the moment, so I can grab it on an XML afterwards, when importing all the shots in Final Cut.
- GH6 and GH5S have freerun timecode support, I am looking for good ideas and apps that I can use for this use


I have identified the app Lumberjack  fcp.co/final-cut-pro/news/1415-the-lumbe...ut-pro-x-is-released

Do you have any other/better idea I should try ? 
Thanks