Even if this is a bit out of my normal experience, and as no one else has responded: Do you have a sketch or an actual brand/marketed product (spoolvalve?) in mind? I had trouble googling up a spoolvalve suitable for your description!
Pressure?
The available size of common spoolvalves seems to be limited, and perhaps you want to increase the capacity by increasing the velocity? The velocity referred to is near a maximum of what you could expect to use for water in pipelines, while oil in hydraulic systems will go higher.
Could you have a look at both for similar valves on the market, types and capacity giving practical flow speed limitations?
Note that cavitation seems to be a problem for spoolvalves (high pressure, fast changing pressure in valve and pipeline during operation and closing/opening?)
Be sure that your product actually exists commercially available on the market and will perform within your limits troublefree over the time required!