Big ups Dan!
The specified limit for a USB cable is 5m due to the round-trip time delay for the signal. They pad it a little and I bet one could actually get away with a 6m run. With the silver conductor in the Silver or Platinum WW I bet the signal would even propagate even faster and would be okay with the longer lengths. Seems to work well for Ivan.
I try to go with the shortest length possible to be able to afford the best cable. Currently, I'm running a 0.5m and would even go with the 0.3m cable if I could.
Sounds like a brave new world in which you have embarked with the K-03 and the WW Platinum!
Can't wait to hear some feedback playing DSD128 files through that wire and the K-03!!!