What's your hurry? I understand the appeal of the R1, it's loud and fast and very cool, but it is also expensive and costly to insure. On normal roads, at legal speeds, the R6 can do everything the R1 can do. The 250 can go fast enough to lose you your license, and is cheap and easy to insure. For a new rider, insurance is often quite a burden.
My point is, each of these bikes has their own strengths, and are more than capable of many years of enjoyment. Don't be too fixated on getting to the biggest bike you can, as fast as you can - you'll miss a lot of learning in the process.
Ride the 250 until it can teach you nothing more. Take it to track days, get advanced training, maybe even try club racing. When you're ready, move up to the 600. Repeat. If you ever master the 600, you'll truly be ready for the 1000, but few people rarely get that good. I guarantee, the great majority of guys you see on a R1 are not capable of riding the bike to its real potential. They're posers.