Z/28
F 19x11 +11 305/30/19
R 19x11.5 +32.25 305/30/19
ZL1 1LE
F 19x11 +11 305/30/19
R 19x12 +41 325/30/19
use this tool to understand the size variance with the rear
https://www.rimsntires.com/specspro.jsp
Additionally a few people have reports with different size tires on the rear v the front, the Z/28 traction control, ABS, Stability systems get upset