22-250, and don't sweat the twist. It'll be fine with up through 60 gr's. If you want to get fancy, you can always rebarrel it later, but meanwhile you'll have a good little rig for what you intend, and a 22-250, even twisted 1-14", is still a hell of a lot more rifle than a 223.
But I'm also in agreement with those saying go straight to Creedmoor and bypass either. But you didn't ask that
“Perfection is Achieved Not When There Is Nothing More to Add, But When There Is Nothing Left to Take Away” Antoine de Saint-Exupery
