Full soft is usually ample for the road on any kind of sporty half decent shock setup...
Usually the high shaft speed stuff is setup and fixed, you only have adjustment of the low shaft speed part for fine-tuning handling balance mainly, rather than bump/ride comfort and outright grip potential on variable surfaces (ie, the road where it's not glass smooth)
It is a fine art though, and no one thing is ideal, it's all down to your personal preference, but as said, often full soft on a good damper is probably perfect for most road users. The advantages of better dampers at all is often their inherent superior qualities such as more rigid shafts, lower unsprung weight, better against overheating etc, rather than just being firmer.
Dave