Surge

I bought a second hand J-Spec S4 Turbo engine which is missing the Air Flow Meter and ABV.
RX-7 spares are hard to get in my part of the world so I want to use an after market CBV. However this is the first time I've ever worked with a turbo system so I have a couple of noob questions.

Question 1:
What pressure is the ABV supposed to open at? I searched the forums and the FSM and couldn't find the answer.
I assume it should open at a pressure a bit above the waste gate activation pressure otherwise the air will be constantly recirculated through the turbo during normal driving and not just during rapid engine deceleration.

Question 2:
Where is the pipe for the ABV located on the engine? The FSM wasn't very helpful and since the ABV, pressure sensor and piping with restrictor pill (orifice) are all missing I can't figure out where it is.

Thanks