Expanding/charging an existing 24V 280Ah bank? (with mismatched packs)

[zorrobyte]

I currently have a self-built 24V 280Ah bank with a Victron Multiplus 24/3000/70. I do plan on doubling-ish this for AirCon runtime.

I would be using an outside storage compartment (sealed, not exposed to elements, but also not heated/cooled) for additional capacity so a heated battery is a must!

I've been considering 2x SOK 12V 206Ah LiFePO4 Battery Bluetooth&Built-in heater batteries in series. Apart from ensuring they are at the same SOC initially, do I need to do anything special to ensure the Multiplus charges all of them to the same SoC considering they don't match capacity? Or.. would I be better off building another 24v DIY pack and figuring out heaters?

Thanks!!