Ok, that has helped alot. I assumed you were talking about a hotwire type AFM not a potentiometer flap type.
Everything you say is right, but i don't think it will work. The problem is that it is a very haphazard way of controlling the fuel. It rely's on you getting AFM and injector sizes PERFECTLY matched to the boost and engine characteristics - very unlikely! More likely than not you will end up with an engine that runs very badly if at all. You need much finer control over the whole rev range as the load, boost and temperatures change. This means an aftermarket fuel controller. It will make thing easy to adjust help liberate a few ore kW! You will be dicing with death (of the engine) if you run a turbo/supercharger with a stock NA ECU.