Late to this thread but I am new to the VSL Steinway D274. Bit the bullet and purchased the full library. I use a Roland FP 30X and spent a couple of weeks tweaking the D274 to try to get the best sound. Then I stumbled upon a Youtube review of the FP 30X and it showed a brief view of the D274 velocity curve. I duplicated it and it made a huge difference as it plays nicely with the FP 30X keyboard. Lots of nuance and at lower velocities and plenty of volume at the upper end of the curve.
I modified the Player preset as seen here, for headphones:

I also have a version that I use with a quadriphonic speaker set up. The only tweak is that I send Main-C and Surround microphones to the second output channel for the rear speakers. It sounds pretty good in the room.
The velocity curve I use is here (with the code below).

{
"data": "[[0.0,1.0],[0.056213,0.928057],[0.121302,0.83813],[0.180473,0.769784],[0.239645,0.701439],[0.298817,0.640288],[0.360947,0.582734],[0.43491,0.52518],[0.505917,0.489208],[0.576923,0.438849],[0.636095,0.406475],[0.698225,0.352518],[0.763313,0.298561],[0.825444,0.244604],[0.890533,0.165468],[0.943787,0.0899282],[1.0,0.0]]",
"id": "velocityMap"
}
I hope this useful.