LifePO4 batteries are nice and will last a long time if you keep them happy by charging/discharging at 0.2C rate or less. The more one charges/discharges over the 0.2C rate, the shorter the battery life. Also, keep that battery out of direct sunlight and warm in the winter.
A 100 Ah LifePO4 battery has 0.2C rate of 20 A. Yes, Bioenno says you can charge/discharge at a higher rate with their batteries (and I don't mean the pulse/surge) and that is not a lie. Your battery life will also be reduced when you do that. Call them and ask. I am not a battery expert. Getting three years out of your LiFeP04 battery instead of 10 may be fine. We're all different.
Running a Yaesu 891 at 100 watts can pull 23 A per Yaesu specs. If one is transmitting in sunlight using a 100W solar panel, that's going to knock off 5 A from the battery draw so blast away with 100 W while the sun is out.
Here is something to consider, my Yaesu 897D pulls 21A at 100W and only 10.9 Amps when at 50W. The signal is only down 3 dB with the lower power, but I'm saving about half the amps. This means I could get away with a LifePO4 50 Ah battery when considering the power draw. If one talks too much after the sun goes down, get the 100 Ah and turn the power down even more if you can.
* I saw that 16 Ah Miady battery the other day. I was planning on picking up a 20 Ah Bioenno, but for $45 I'll risk it and see how well it lasts with the Icom IC-705. I can use it for other low draw ( 3 A ) stuff if I don't like the results with the Icom. I have the 6 Ah Miady and I haven't had any issues with it thus far, but I don't use it to power a 100W radio.