I don't think your "below the waist" feel is broken at all. Revisit this and then compare what you were riding vs the new tires.
https://www.ninjette.org/forums/showthread.php?t=258160 Some of those comments will sound really familiar after our time actually doing it on track... a little harder, a little harder, a little harder each lap ya know.
Lemme know what you think after your next track day please.