We just did this with some 2860r-7's, was told the Garret 2860r-5 actuators open at 16psi and I believe the HKS actuators open around 15psi (my GT-SS's arrived this week muhaha)
Both actuators have the threaded arm, so you can adjust the reach - so yep they are adjustable.
Edit: They are good for whatever as long as it is over the base pressure (so 16psi+ or 15psi+). Just depends how much air you bleed of the line that connects to the actuator - leave this disconnected and they might just never open. The turbo however, will break...