What ever you want really the spring will hold it to the designated pressure or near enough anyway. so say if it's a 1 bar spring and your driving around upto around 14 psi or so it won't dump fully will flutter
That was at 1.5 bar I'm pretty sure it's still got a few more psi left in it. But when it was on the dyno it stopped making power down to the head, had valve bounce 300-400 from the Rev limit it still making power all the way up