Yes, you can use a standard 6 or 6.5CM bushing die. I can post the bushing specs tomorrow if you'd like. I only use that for my virgin brass, and then I order a custom non-bushing die from whidden using fired brass. Since I have one of those custom dies already, I can take 6CM brass down to 22CM in one pass. Works fantastic. I order custom sets from whidden, so I have a micrometer seater too. ... but you can use just about any large 22 cal die such as 22-250 or similar and ream out the sliding sleeve.
Our barrels are expensive, so I certainly can't counsel you on what makes most sense for you financially... but I would recommend getting what you think will serve you best for your intended application. The 22 creedmoor isn't even in the same ball park as the .223 regarding performance. Think 22-250 on steroids. The .223 is considerably smaller. We don't do 223 conversions, but have chambered these rifles in more different cartridges than any outfit on the planet. So if you want something on the 308 bolt face and bigger, I'd be happy to help.
Our barrels are expensive, so I certainly can't counsel you on what makes most sense for you financially... but I would recommend getting what you think will serve you best for your intended application. The 22 creedmoor isn't even in the same ball park as the .223 regarding performance. Think 22-250 on steroids. The .223 is considerably smaller. We don't do 223 conversions, but have chambered these rifles in more different cartridges than any outfit on the planet. So if you want something on the 308 bolt face and bigger, I'd be happy to help.