I have a Ninja 250r and I do think you will find it too small. Not because of the low seat height, but for the very short distance from the seat to the bars. It might feel quite comfortable in the showroom, and even when you are just getting started at low speeds, but as soon as you get onto a bit of open road and hit some twisties, you will wonder why you can't get the damn bike to turn in properly. And the answer will be your lack of leverage on the bars. I am only 5'7 and I notice this issue. It wasn't until I had a ride on a mate's SV650 that I noticed with the more stretched out riding position how much easier it was to counter-steer into corners. I would by some Woodcraft clip-on bars for mine to get a better riding position if I was planning to keep it for any length of time.
Good luck.
b.
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