Do I need to "top off" the battery if it is fully charged?

I think in general the answer is yes depending on your charger. I notice on my "smart charger" it will say full when charged and shuts off. I don't think it ever gets to 100%. If I charge for a couple of more days with my old Magnatec single stage charger I can get a few more days of dry camping before my batteries get to 50% SOC. 5 days vs 7 days. I do use the equalize function on my 40 amp B&D charger several times a year which is a much higher voltage.