A couple of tips. One is go to the hardware store and pick up several widths
of metal dry wall knives.  Like a putty knife but more flexible which makes a
huge difference.  Those will save a lot of time over the squeegees since they
can cover the area faster and more importantly, more accurately.  Get 2-3
widths.  I have 6", 8" and 10" I think.

For fairing, build a "mold" of the surface, i.e. get some G-10 fiberglass
(circuit board glass/epoxy, really versatile material), aluminum sheets (a
metal straight edge is pretty good) or whatever, and wax the surface with
mold release.  Note that even wood is a good material when coated with mold
release wax or tape over it with plastic packing tape for a smooth surface.  
Next, putty the area you need filled then clamp/screw/weight down the "mold"
to conform to the contours.  When hard, peel the mold off and you'll have a
perfectly contoured surface.  This may still require some spot puttying since
you will probably have some bubbles but it beats a lot of sanding.

By the way, one trick I developed years ago for large fairing jobs.  I did
this while I was building my 37' racing sailboat and also when I had to
attach a new bow to the boat after a collision. Take a fairing batten,
(fiberglass, metal, whatever) and wax just like above.  Then bend it to the
surface to be faired.  I then packed putty under the lows in the batten and
when hard, was removed to a perfectly fair shape.  I would do several of
these a few inches apart so that I had a "grid map" of the lows.  Then all I
had to do was fill in between the strips of this perfectly fair putty.  I
would normally add a tiny amount of pigment to the new resin so I had a
contrasting color to denote the old and new putty.

I still had to do some long board sanding but it beats the Hell out of trying
to do it with putty knives and sanding alone.

And don't think of it as sanding, think of it as "Low impact aerobics".

Hope this helps.

Dan Newland