Not knowing exactly what you have (internally, not marketing lit), it's hard to recommend anything. If it has a MPPT controller, you want to match Vmp between the panels as close as possible for best efficiency, but a few tenths of a volt isn't a big deal. PWM is less picky, Vmp within a volt or so should be fine. Store at 100% is for lead-acid, not lithium. LiFePO4 can be charged to 98% with voltage as low as 13.6V, but it takes longer. Anything over that is a compromise between battery life and charge time, but recommendations have trended down from 14.2V to 13.8V over the past 5 years. Other lithium chemistries take different charge voltages.
Shelf life is best at 20% to 80% charge and temperatures between 0C and 20C (32F to 68F). A study on this is pointed to by my LiFePO4 resources page on my blog. Temperature makes more difference that state of charge.
