Withuot being able to bring and hold the bateries to a proper absorption voltage for a proper duration and possibly perform an EQ charge afterwards, there will likley be no improvement to the battery condition, and just a lesson in futility.
Getting a charging source to do what is needed, seems to be impossible when there is anything 'smart' and 'automatic' involved, and the WFCO is a drooling knuckledragger that tries to be smart and automatic.
Get the batteries to 14.8v, hold them there until amps taper to ~1% of capacity. Then slowly Raise voltage to 16.2v, hold then there until specific gravity no longer rises or amps start increasing along with a fast rising battery temperature.
Adjustable voltage power supplies might be manual chargers, requiring a human to decide what voltage to allow and for how long, but at least they can actually fully recharge a battery and not require sacrifices to chango while hopping backwards of one foot counterclockwise chanting 'just fine; just fine, everything will be just fine'