Bang on mate

My amal valve is exactly as u have described, has just been sat there chilling for the past 7 years....

You can run amal's with more boost no problem. There are a million ways of acheiving the same result.

In the future, once u have an idea of how it all works, u can try replacing the bleed valve with amal - then wire the amal to a switch inside the car, and have a high/low boost switch