I have successfully installed Sunset Valley switch stands to work
with  Aristo short radius and large radius turnouts.  The procedure is
relatively easy, and can be done by any modeler that wishes to have more
realistic switch throws which positively lock the turnout in the
direction selected.
      The first step is to remove all the plastic Aristo mechanism that
is attached to the track.  New blocks (extension ties) must be cut from
hardwood.  I used 3/8" X 3/8" hardwood dowel that I found at Lowe's.
This is sold in 3 foot pieces, and can be found in the lumber section
with all the hardwood trim pieces used for furniture work.  I cut my
blocks 4 inches long, with two being required for each turnout.
       The next step requires a sanding drum in a Dremmel tool.  Mark
1/2" on the end of one of each of your your blocks.  Use your Dremmel at
slow speed to cut the top and sides so that the 1/2"  end fits snugly
into the hollow end of the Aristo turnout ties.
        Take all your blocks and soak them in a wood preservative that
is used for below ground applications.  When dry, they need to be
stained to match the Aristo ties on the turnout.  I have found that the
Aristo ties are not dark brown, but more of a dark slate color.  I had
some solid stain from Home Depot that was actually slate (Behr #376),
and in the sun, it was a close match to the Aristo ties.   Once your
blocks are stained,  they are ready to install.
         The tapered ends are fitted into the hollow Aristo ties, and a
pilot hole is drilled into each one.  They are then secured to the
Aristo turnout with small brass screws through the original holes that
held the plastic turnout motor that was removed in the first step.
          Follow the instructions provided by Sunset Valley to fabricate
your throw rod.  I used 1/16" brass rod which was easy to work with.
          A hole must be drilled in the plastic throw of the Aristo
switch to accept this brass rod.  Make sure you drill this hole inside
the original slot (closest to the turnout).  Place the rod in this hole,
and then take your switch stand and mark the location for it on your
blocks.  Please note that the throw block and pin on the bottom of the
switch stand shaft must align with the lever on top.  None of mine did,
and I had to use a very small allen wrench to re-align everything.  When
the switch is set for the main route, the target is not seen by the
approaching train.  When the switch is set for the diverging route, the
target is seen by the approaching train.  You will also have to drill
out the four mounting holes in your switch stand before it can be
permanently mounted.
           The switch stand is attached to the brass rod, and then is
screwed to the blocks using 4 small brass screws.  Work the mechanism,
and re-adjust with the set screw and allen wrench as needed.
           The switch stand can be painted.  I would recommend an
airbrush with a fine tip so that the mechanism does not get fouled with
paint.  Floquil Poly-S is water based, and seem to do a good job.
Remember to check your prototype for the colors on the target.   On my
railroad, stub sidings have red targets to show that the switch is
aligned for the siding.  On passing sidings or any through tracks,  the
target is yellow on one side to show the oncoming train that it will
enter the siding.  The opposite side of the target is red, to show the
train approaching from the other direction, that the switch is thrown
against it.
            See attached photo. Note I have not stained these ties for
better visual effect in photos.

  This tip comes from Jon D. Miller who lives up in the Roanoake, Virginia area.
  Many railroaders wish to add realism to their layouts, especially when it comes to turnouts.  The standard switch machines manufactured by Aristo and LGB look too toy-like to many modelers.  Sunset Valley manufactures a line of switch stands and ground throws for Large Scale that look very prototypical.  The problem is how to install them to operate the Aristo or the LGB turnout.
  To properly install these units, the ties must be lengthened on your turnout.  The switch stand must be mounted approximately 2 3/4 " from the rail on the mounting side of the turnout.  The throw is 3/4 " wide, so two ties must be lengthened on the mounting side.
Cut hardwood ties to the dimension of the Aristo or LGB ties.  The hardwood ties are butted up against the Aristo or LGB tie on each side of the point bar.  Ties are cut to a length that allows for the throw bar (Sunset Valley provides a diagram of the throw bar that includes all dimensions).  It is best to add enough length to accommodate the switch stand plus a little to extend past the switch stand.  All extension ties are first soaked in DAP Below Ground Preservative and allowed to dry.  These ties are mounted to the turnout using Titebond weatherproof glue and wire brads.  The switch stand is also attached to these wood ties with wire brads. 
  You will have to oil the switch stand pivot from time to time.  The switch stand is brass, so it obviously does not rust, but it does get dry and then will start to bind.  A little oil from time to time takes care of this problem.   This should be done about four times a year in our climate with all the rain.
   Sunset Valley also makes ground throws that mount in the same manner.  Ground throws should be used where clearance is a problem, such as in yard trackage. 

SV Switchstand installed on an Aristo switch.
Note the wooden tie extension and the
brass wire throw rod.