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It might be advantageous to you to ask this question at solarpaneltalk.com also.
For LFP life cycle, I think the difference in 20˚ and 25˚C is minuscule, and not worth the trouble. Although, colder temps would be recommended for storage, maybe 5˚ to 10˚C.1
The Whizbang jr. is really a battery monitor that measures the amp hours that go in and out of the battery. So, it can give you a fairly accurate measurement of the state of charge (SOC) of the battery. The Wihzbang jr. comes with instructions on how to install it and configure the Classic to use it.
The charge controller's job is to charge the battery. It applies current at the battery terminals. The inverter is also connected to these cables. If the load by way of the inverter draws current from it's connection to the battery, the charger will try to compensate by increasing the current. If it can't supply enough current, then the battery will make up the difference. When the load drops, more current will flow into the battery than the loads. This can happen in any charging stage, bulk, absorb or float. This will happen without any configuration change.
Being already over paneled with 2 strings of 4, another string would be excessive. If you realize that this system configuration does not meet your power requirements, then the next step would be to add another string of 4 batteries and possibly another string of panels.
Two strings of panels will require circuit protection, well not required, but it's good to have them on breakers for troubleshooting. A combiner box with two 15 amp DC rated breakers would work well for this. Here's a link:
https://www.solar-electric.com/mnpv3.html and the breakers, https://www.solar-electric.com/mnepv.html
You will need a DC breaker or fuss in the neighborhood of 80 amps between the charge controller and the battery. I recommend using #4 AWG wire for this connection. Also a DC breaker or fuse between the battery and the inverter, recommend a 125 amp breaker with 2/0 AWG wire, keep all DC cable wiring as short as possible, the link for both CC and inverter battery breakers:
https://www.solar-electric.com/pamodccibr.html and https://www.solar-electric.com/mnedc125.html
A box to mount them in: https://www.solar-electric.com/mnedc-quad.html
Keep in mind, the low battery voltage shutdown feature of the inverter is to protect the inverter, not the battery. Inverter specs also state high voltage protection is 30 to 34 volts. Equalizing voltage for the T105 battery bank can be above 32 volts. Hopefully this won't be a problem.
I'm sure Mcgiver will comment soon, but I will comment on a couple of problems. This particular panel is most efficiently used in a string of 2 ( 2 panels in series) to charge a 24 volt battery. The other problem is that a 24 volt 225 amp hour battery bank can take a maximum of about 30 charging amps. A single string of 320 watt panels will produce about 20 charging amps. This is a 9 to 10% charge rate on your 24 volt 225AH battery bank which will work. If you want to use 2 strings of panels (4 panels), I would suggest limiting the charging current in the Classic 200 to 30 amps. This will improve low light wattage production and produce more power throughout the day. This will work better.
Rerun the string sizer with 2 strings of 2 panels and see what you get.