As I have almost the same setup (although mine is 12S2P), maybe I can help a little.
42V Charging-Voltage should be enough. That means each Cell ist provided with 3,5V which should equal about 95% full. The charger I plan to use for overnight charging will use only 40,7V which should get the Batteries around 80% full (which is said to be near the optimum for battery-life).
My old charger cuts off at 43,5V. I will keep that for topping off the Batteries before really long drives. But being kept at that voltage for prolonged periods (i.e. every night) will significantly harm the batteries in the long run.
The old charger (the one with the high cutoff-Voltage) I bought there:
https://www.akkukaufhaus.de/ladeger...10a-lifepo4-ladegeraet-fuer-life-akkus?c=3769 But I must warn you: I just recently discovered, that this charger will rise the charging-voltage even above 43,5V to keep the charging current up right until the cutoff happens. And the charging resumes as the batteries drop below 43,2V until the batteries are above 43,5V again. So this charger will fill the Batteries to 100% SOC, which will damage the batteries in the long run, but it is still handy a few times each year - be it for long-haul trips or allowing for top-balancing to be done.
The new chargers I got from
@Martin Heinrich , which are basically just Power supply units for electronics, can be adjusted in the maximum current and the voltage.
As soon as I can trick the BMS of my EL to monitor the charging with these, I will use one daily with a Voltage-setting to about 40,7V. This should optimize battery life. The maximum achievable current is about 20A, but that drops to around 2-3A when the batteries are full. It will not become 0A ever. That is just how LiFePo4-batteries work.
Anyway - the current will decrease significantly as the Batteries gradually fill up. That's why I turned up the voltages of the ones I intend to use as a quick-charge option for long-haul trips to keep up a high charging-current for longer. There should be no harm in that bechause on these trips I presumably hardly ever will have enough time and patience to risk overcharging the batteries. (Just to be sure they will not exceed 43,5V. I quite like my batteries and don't want them to die early.)
If you use a CHARGER - make sure that it is suitable for LiFePo4-batteries!
Chargers for other chemical compounds might likely damage your cells by using wrong charging-patterns.
If you use "dumb" power-supply units make sure they are set to the right voltage and are capable of limiting their output-current. Otherwise you might damage your cells or the unit.
The charging-pattern for LiFePo4 is CCCV (constant current - constant voltage). That means the charger has to limit the charging current as long as the batteries will consume so much power to not allow it to come up to its voltage-setting, but as soon as the voltage can be met that has to be maintained while the charging-current gradually decreases.
Keep in mind that the EL will allow for battery-currents above 100A, so you are able to put significant strain on your cells. That means you should maintain a steady temperature for those. Putting them under that much stress at freezing temperatures might damage them which leads to premature degradation. Keep them above 5°C - better 15°C but under 45°C - better 35°C for getting the most lifetime out of them. (Cycles are not that important. Those are most likely never met in the battery's lifetime anyways.)
Hope that helps.
