How were the group 24s treating you?
Do you plan on adding more house loads in the near future?
How are the batteries being charged?
without knowing anymore specifics of your vessel, and if she was mine, I would:
grp 27 start and grp 27 deep cycle.
and AGM is a type of lead acid battery. You have three types of lead acid: Flooded, AGM, Gel.
they all have their pros and cons.