Question, the overwhelming opinion of this group is that the Norris planes
are much better at final smoothing than the Stanley's. The question is, why?

I've heard two differing opinions. One, that the Norris' adjusters and
precision allows it to take a more consistent cut thickness. This permits
it to be adjusted to a thinner cut. Another group claims that the Stanley
can easily cut a thin enough slice but the planes basic design works
against it, it's too long and not heavy enough. 

Any comments?

I was thinking that a simple modification to the 604 could be made to add
ballast to increase the plane's weight. Though this would ruin the plane's
value (and probably cause most of you to throw stones at me!), it might
make for a better plane. Has anyone ever experimented along these line?
Before I buy a 604 just to modify it, I'd really love some feedback. Also,
does anyone have a 604 that's heavy on "patina" but mechanically sound that
is available for less than museum costs? One they wouldn't mind knowing was
being used for such genetic recombination experimentation? Perhaps one that
permenantly disfigured a loved one (OK, can that last one. I forgot, this
isn't rec.woodworking.powrtools).

I understand there is a 604 type that has frog adjustment with the irons in
place, is that true?

Thanks,
Philip 

God First, 
Your neighbors as yourself.
All else is commentary.