Hard to diagnose the 14.4V issue because we don't know if the converter kicks into absorption cycle when the solar charge is removed or if your batteries are seeing 14.4 all day.
I'd suggest to look over the controller manual and make sure you have all the settings correct. Some controllers need to be manually set to achieve lower float voltage, not sure about yours.
As was stated above, Trojan 6V batteries like a higher voltage, 14.8V and above. Following the Mfg's suggested charging schedule will make sure you get the most longevity from the batteries. Good luck with your new system!