Gentlemen! I have to share this with you!
I decided to take a test ride with CX rear spheres for a couple of days (two new 450cc spheres found at my service garage waiting for nobody, instead of regular 300cc). Wow! The effects are instantly noticeable: the vertical amplitude does not increase but the oscillation is slower and fades away somewhat later. The car is softer but it doesn't affect the overall stability roll and steering (I assume it would be critical if front spheres were replaced too). The hard mode is still hard enough but allows better bump absorption.
On the negative side, all I noticed is that it dips a bit more on the traffic light brake release. Are we aware of any other downsides of this experiment or should I just continue? Thank you for your opinions.