I've been probing this myself for a few hours but I'm close to being completely stumped. I can't find any resources on this
I've added the following:
1. An appropriate Mod_StatsHandler_Type with settings perfectly matching exist XenForo defaults.
2. A row for each stat into xf_content_type with ('stat_type', 'addon_id', 'serialized array pointing to my class')
3. A row for each stat into xf_content_type_field with ('stat_type', 'stats_handler_class', 'Mod_StatsHandler_Type'
I still do not see my checkboxes on the daily statics page, though. What am I missing?