Originally Posted by Simpler=Better

It's really not hard at all:

Apply vacuum to the actuator, closing it to spool fast.
Tee in as many boost points as you want, and isolate them with electric valves.

This way, you have switches in the cabin for(examples):
Relaxed vanes(highway)
8psi (moderate driving)
12psi (full boost)
18psi (methanol sprayer)

I had mine setup with relaxed & 18psi and it worked great-boost at the flip of a switch.