filmscanners: "Working space" RAW file in Vuescan

[Ramesh Kumar_C <RKumar_C@zaplet.com>]

Hi
     By reading "Real World of Photoshop" I got some idea about the "RGB
Working/Editing space".
I also started using Vuescan and I loved the technical guide which comes
with Vuescan, its makes the complete process transparent to the user.

I use "Minolta Dimage Sac Dual II"


I have few questions, please answer them

a) My negatives have lot of dust and scratch and they are very apparent in
the scan output.
    How can I reduce the dust & scratch?. 
    Vuescan documentation says I channel is needed for removal of
dust/scratch. 

b) Recommend a "working space" to be selected for RAW scan in Vuescan?
    I know it depends on many factors but still let me know your opinions
about it.

c) How does the "working space" affect the RAW scans, since it is supposed
to be RAW scan.
    I think bigger working space increase number of colors and thus a bigger
RAW file, Am I right?.


Thanks 
Ramesh