Boost controller

Hi, I have a turbo foxbody. Flash arc/on3 a bunch of other stuff h/c/I. But my question it about controlling boost.

I want to ditch the manual controller and go electric. I can't figure out how to get my mega squirt to do this. However, I'm wondering if there is a simpler way.

I have a Mac 3 port valve, I'm looking for a way to control it. Can I use a pressure switch. Normally off till it sees 15psi??? Or is there a gauge that would send power or ground to the Mac valve???

I'm really not looking to spend a ton of money on this. But I used to have a pressure switch that would turn on a relay for a water meth pump above 10psi. Or am I reinventing the wheel???

So I have ms2 v3.57 I can get the Mac valve to operate if I touch it to the iac1 outs on the boards. If I soder wires to them to run to the front of the car I get an error. I know it's not the right way. I have looked for fidle pin. I have not had much luck finding this.