The T56 Magnums shifts incredibly nice.... the TKO600 was designed many a moons ago and isn't even in the same ballpark.
Of note- I'm pushing 1400hp thru a stock T56 Magnum

in my 88mm turbo LS9 RX-7 1/2 mile car. It shifts easily at 7800rpm....
There is a guy running one behind a 2JZ in a Supra shifting at 10K RPM making 1500rwhp+.... full race quad Tilton small diameter clutch.
__________________
Project: 1969 Chevelle, alum 5.3, GTS76 turbo, Chiseled Perf A/W intercooler, Holley Dominator EFI, Davis TC, JRi coilovers, 14" brakes, T56 Magnum. CTS-V Recaro seats!
Coffey Fabrication Nashville, TN doing the fabwork! 800rwhp+/25mpg+/9's@150mph goal
https://lateral-g.net/forums/showthread.php4?t=52976
1993 Mazda FD RX-7, built LS7, T56 Magnum, Holley HP, Davis Tech TC, 8.8" 3.73 Cobra IRS diff, DSS axles, Ohlins coilovers, big brakes.
CCW 18x11 front 315/30/18's and 18x12.5 rear on 335/30/18 RA1's,
2850lbs
10.31@137mph 165mph Shift-Sector 1/2 mile speed
441ci AllPro headed motor and 200lb weigh reduction in the works....