Interest in flooded batteries has waned to the vanishing point.
Years ago I furnished a lot of information to this site which was then proprietary.
Included was a rather concise interpretation of using an adjustable voltage but constant potential charger called a Megawatt. They are 29 or 36 amp dependent on model.
Times change. And now there is little interest in flooded batteries, minimum charge time, and maintaining batteries for the most longevity.
I then opened up the Megawatt and upgraded the weakest links inside, added an external voltage control and finished up by redesigning the unit into a 56 amp unit.