For a street build, a single 12awg is sufficient for the main terminals. Accordingly, 2 x 14 awg (or 3 x 16awg etc…) would be plenty of current capacity for the series connections.
If you really wanted some headroom, terminate your main terminals with 10 awg and then use 2 x 12 awg or 3 x 14 awg (etc…) for your series connections. This is overkill but will let u drop this battery into a more powerful build thereby future proofing it.
Make sure you’re using high-strand count silicone wire.