As ever, the information is in the manuals, please read the NG battery manual and the NG BMS manual.
The BMS controls the multiplus charge voltage.
The BMS asks for either 14.0V (absorption) or 13.7V (float). 13.7V keeps the batteries just below 100% and avoids overcharging which is good. 14.0V is required for balancing so you need some time in absorption. The manual says 2 hrs per month for lightly cycled and 8 hrs per month for heavily cycled.
The BMS has 2 settings, SOC threshold, default 70% and repeat absorption interval 30 days. You change these to suit your use. Basically, the BMS stays on float all the time unless the SOC drops below 70% or 30 days goes by since the last absorption.
You could set a daily absorption or a 90% limit. If you have more frequent absorption then you need to reduce the absorption time from 2 hrs to 15 min for daily absorption.
Personally I am happy with the way NG works, I think it is much better if you are not cycling a lot to stay just below 100% rather than overcharge them.