For a new converter may I suggest a Progressive Dynamics 9200 model This is a stand alone Wizard controlled multi-stage converter.. I have yet to find one better for use with Flooded wet cells.
For batteries.. I truly like GC-2 where practical (or the larger L-16 I think they are) These both fit the same footprint as a Group 24. but are taller..
GC-2 pair is 220 amp horus give or take, DEEP CYCLE so you can use half (V/s about 1/4 on a Marine Deep cycle) The larger one is 2x that OF coruse they are also heavier (Same pound per amp watt hour as the others so a GC-2 weighs about the same as a 110 Amp hour (Group 29) but you can use 2x the power)
They do need the occasional drink of distilled water however.