Get some insurance quotes, too. With my insurance company, a 500 is less expensive than a 501+. (I think they're considered sub-sport.) A 600 supersport would probably cost more than a 650 sport-tourer. My 650 cost more than double my 300. Not sure about a 1000.
When I started riding--going into my 3rd season now--I decided to take the progressive approach, starting small. Went from a 300 to a 650 recently. In the future I might want a different feel, but, even though I'm getting used to the power difference pretty quick, it seems like plenty for how I ride right now. (I don't know about the suspension.)
I found Australia's LAMS guidelines to be reasonable. Also considering how race classes start with lower power bikes. Better to focus on skills and mindset than raw power, at least for a little while.