For adding observations from custom data_bindings, please have a look at https://github.com/Daveiano/weewx-wdc/wiki/Custom-data-bindings

You can add new observations by adding them to stat_tile_observations (in [DisplayOptions] in skin.conf).

# What to show for the stat tiles.
stat_tile_observations = outTemp, outHumidity, barometer, ..., new_obs

First, define the appearance of the new observation. To do so, add an entry to [DisplayOptions][[diagrams]] - look for a comment # Observation specific settings. - the definition should go there:

[[diagrams]]
    ...
    # Observation specific settings.
    [[[new_obs]]]
        type = line
        color = "green"

Second, add your observation to the report pages (day, week, month, etc) by adding them to e.g. [DisplayOptions][[diagrams]][[[day]]]:

[[diagrams]]
    ...
    [[[day]]]
        aggregate_interval = 1800 # 30 minutes
        [[[[observations]]]]
            [[[[[new_obs]]]]]
            ...