You can do the harness with bullets. I prefer andersons. The risk is lower.
You can tape all the bricks together and gather the connectors.
now you have 6s4p
This is the view from another angle.
Now you make the series section cable
if you plug it now you have 12s2p use it for discharge.
for charge again you need to make not her parallel section as the one you have in the lipo pack.
And get an end-user harness for the balance.
and you are done. You only have to plug/unplug the series cable to use it. If you get a bulk charger you use the series cable to charge as well.
bulk charge has some risks so you better don't Rush it to 4.2v 4.15 or 4.10 is enough. Balance the pack at least once every 10 charges. It is better if you do it often though. I do it once every two charges.