Ultralightweight/ULW Bike Search

I asked a question earlier and I got some seriously good feed back. I figure I will give it another go.Here is the previous discussion thread: https://www.reddit.com/r/Trackdays/comments/ew6hv7/motorcycle_track_classifications_amateur/I am considering the following bikes.Ultralightweight/ULW: Yamaha R3's, Ninja 400's, CBR300R (But probably a bit small at 286cc), GSX250R ABS (almost certainly too small in the displacement category)I am 177cm tall and about 71-75kgs, but my race weight is closer to 71-72kgs. That pulls me towards the larger displacement Ninja 400. I have sat on both off them and cannot really tell which one will be better ergonomically. I would probably replace the windshield on the Ninja. In the looks department it is Yamaha, hands down. I also want to buy a bike used.Questions for the forum:Am I correct in thinking the Ninja and R3 are the best ULW platforms? Should I reverse my thinking about the Honda and Suzuki?With my height and weight is it going to be impossible to perform on a ULW?Where do you suggest searching for one of these bikes used? (websites, specifically)Is used the best way to go (I usually buy used vehicles) or is it better to have someone just do a custom build...would that save money?Any other questions I should be asking that you would like to provide answers to.Thanks! via /r/Trackdays https://www.reddit.com/r/Trackdays/comments/f84g8t/ultralightweightulw_bike_search/?utm_source=ifttt