Need help finding correct SOC/Voltage for lifepo4 batteries

solarpowernovice

I have upgraded from golf cart batteries to 4 of these https://www.litime.com/products/litime-12v-100ah-lithium-lifepo4-battery and I want to make sure I program my midnite classic 150 correctly before I turn on power from the solar panels. They are connected in series/parallel to make a 24v 200ah bank. I have already updated the classics firmware.

I've heard that it's hard to find the correct state of charge through voltage alone... Is there a method to make sure I'm inputting the correct battery  voltage into the controller before I turn on the solar panels? The batteries manual recommends 14.4v to 14.6v charging voltage with a 2 amp tail current. I will be cutting my negative battery cable and installing a whizbang jr. ,so I can set the end amps and hopefully get more information on SOC.
 
I currently have 3 of these panels https://www.solarelectricsupply.com/solarworld-sw260-mono-solar-panels hooked up in series and 3 more panels that are a different brand, also 260 watts that I plan on hooking up later, after I program the controller for the batteries. This will give me 2 strings of 3 260 watt solar panels, which I'm told is a good match for these batteries. 

Is there any advice you could give me on how to make sure I'm inputting the correct battery voltage on the classic and if there's anything else I need to worry about before cutting on the solar panels to charge these batteries? I've already got everything hooked up and drained the batteries some, using my 2000 watt magnum inverter.

I have the 14.6v charger the battery manufacturer sells for the batteries to charge from shore power. Could I use this to charge each battery individually to 100% and then use that voltage as the "correct voltage/SOC" on the classic? Just a thought. Thanks 

Update: I'm installing the whizbang jr. Today and I'm going to turn the 3 solar panels on to charge at 28.4v (14.2 x 2) volts on the classic (just to be safe) after setting the battery voltage on the classic to battery voltage at battery terminals. Wish me luck!