Yep, that's more than enough. I first got a 6-20 since that's the L2 plug that came with my PHEV's provided charger, and the car can't physically charge any faster than 4.3kW anyway. The only reason we're putting a 14-50 in now is that it's shorthand for "EV-ready" real estate listings if we ever want to sell the house, and the car we hope to get next year can support 9.6kW.