BMS and charging questions

A seller is telling me I can use their 13s BMS for a 12s battery if I just skip the last positive cell end. Is this true?


Supplier’s website

Also in the meantime, while I figure out which BMS I want, can I just charge my 6s batterys one at a time with a friends charger? It can only charge one battery individually so do I have to check that the voltages are pretty much the exact same level before I use them?

Searchterms: 12s Deligreen 13s BMS