I'll just let you know what I did and let you sort out what you want to do...
I did a lot of research and heard everything from start out on a 250 to get a bike you can ride for a couple years to "You're 6'5 so you're going to probably want a litre bike...but nothing less than a 600." Anyway, I bought a used Ninja 250 and learned some skills on that. After a year, I sold it for the exact same amount I bought it for and bought a bigger bike. The little Ninja was plenty fast (will beat almost all common cars off the line) and gave me an inexpensive opportunity to see if I even liked motorcycling and start learning motorcycle skills. If I laid it down or anything else parts are plentiful and cheap. Good luck with your decision whatever it may be.