I think the problem with this is that negotiations are very sensitive to starting terms, what he would pay for (and I think many others would as well) is basically an intelligent idea of where to start.
Exactly. I don't want to know what an employer thinks they can get away with or even what level I can push it to (which may be higher or lower than my 'recommended' level).
To get a proper idea I'd also have to do a lot of interviews. Hence where someone who's got a bit of experience/knowledge in this area can save me a load of hassle.