Well, I've been balance charging 6S packs, and I do not think that balance charging takes any longer than just straight charging. Even if it does, it's an extra minute or two at most.
2 cell packs should hardly require much balancing, there are less cells to balance after all.
It's best to balance at least every other charge, but you may as well balance on every charge - it can't hurt, and you're not that pushed for time at a race meeting.
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