The cost difference assuming you have the breaker space for it is almost zero, so go for 2 x 20. This requires only 1 more conductor.
You can underrate, which is a little safer. Choose 15 A breakers, but 12 gauge wiring. You get the low resistance of the thicker copper, but the safety of the lower tripping point.
Also, you may need a cable TV ground isolator. Might as well get one, they're cheap and prevent ground loop issues later.
You can underrate, which is a little safer. Choose 15 A breakers, but 12 gauge wiring. You get the low resistance of the thicker copper, but the safety of the lower tripping point.
Also, you may need a cable TV ground isolator. Might as well get one, they're cheap and prevent ground loop issues later.