The KYB just have a tough time keeping up with spring rates much over 1.00".
I have blown out a couple KYB's in my Barracuda with .99" t-bars in 16 years. I don't mean they just went bad. I mean they literally puked and dumped all the shock out right out of them in a puddle on the garage floor.
The guys that have run bigger than around .99", 1.00", 1.03" t-bars with KYB report really rough unsettled ride. They usually only run them temporary. The KYB gets progressively worse with more rate. Then they put a good shock on and things change a lot.