[DW SD]

Various folks offer revalving services. It is some black art and some science. If you pay a third party to revalve (not Bilstein), they won't provide their valving #s to you. Though they typically have Bilstein revalve the shocks to their specs.

When companies do custom setups, they often will use multi-way adjustable shocks. They'll drive until they like a setup and then use a shock dyno to measure the shock's characteristics. From there, they can give the spec to bilstein for the valving. Bilstein will sometimes (maybe always) test with their dyno to ensure the shocks meet the specs.
These companies can do a custom setup for you if you provide spring rates, car weight, driving style, desired handling characteristics, etc. Again it is a combination of science, art and empirical testing that determines the final outcome.

Smart Racing -
Bilstein -
Jae from Mirage International in San Diego
Steve at Rennsport
and others.

I suspect any one of these could take your shocks and modify them to reduce the harshness. Harsh ride can be from damping that is too little or too great, as I understand.

Hope that helps. I'm no expert.

Doug