Charging LiFePO4 at low voltage - how do you know when to stop?
Actually you will get MUCH better longevity charging at 13.6v (3.40vpc), at that level you can get to higher than ~98.9% full anyway. 13.8-13.9V is maximum AFAIC.

Stopping at C/50 would be better than C/100, and in fact many suggest a half hour absorption once the battery hits your 13.6 would be fine - less is more, no need to push to "full-full", actually harmfull for LFP.

If you "have to" float, 13.2 or 13.3 probably doesn't reduce lifespan much, but better to "just stop" from the LFP bank's POV.