If you want to test a far better arrangement leaving behind the limitations you just mentioned try this :
1/ PUT A NEEDLE BEHIND THE DAWES ( ie in serie with). MAKE THE DAWES TO OPEN MUCH MUCH EARLIER ( ie unscrew it almost to max, so that it opens as soon as some positive pressure is seen by the dawes ).
2/ SET THIS SECOND NEEDLE in such a way that you reduce the quantity of positive flow being injected into the vaccum hose of the actuator.
3/ DON'T FORGET to set again your first needle as you wish your spool-up to be.
This will make sure the vanes open continuously whilst RPM goes up, and wil get your VNT to work as it should, and not transformed into a stupid two-stage turbo.
Try and find the best arrangement to suit your driving and until you get a continuous rise of boost with RPMs.
Check the MAF value, as only FLOW matters, not boost !!! High pressure & little flow (MAF tension) means higgh back pressure and little efficiency. Smaller pressure and high MAF tension means high flow of air and fuel injected, and therefore POWER.
Your Patrol will run like never before. Believe me.
I have now thrown away my digibooster, and using my Patrol (2000) MAP to regulate the VNT with my own electronics, which allows me to get what I want when I want it.
But the three valves arrangement is the best and cheapest arrangement you can get. It mimics what an ECU would do quite accurately. And works beautifully once you have understood what you do with the valves.
Watch the limp modes though. If the flow of air you get is too high, MAF will be too high, and unless you control/reduce the MAF tension, you'll get limp modes if you push the flow too high. (note : the FLOW, not the boost).