As 10 to the -3 power is .001, and the Hoke Cv chart has it max out at .85 Cv (times 10 to the -3 power) at 18 turns, the Cv would indeed be about 0 to .00085 (again, according to the info from Hoke). I bought one of these a while back just to play with, and have not done so yet. I'll try to do that this weekend and (try to) compare it to maybe a Swagelok S or Hoke 1300 (1d). Though differences on that scale start to be tough to catch, but I'll do my best.
Then again, I might have to order some more Gyrolok ferrule sets (Hoke just had to make their compression fittings "special") so it may take a couple weeks. Or somebody else can chime in.