This Ski design scales really well, I have printed sets as small as 40% for small fomies and as large as 130% for 40 to 60 size planes. The pictures are of version 2, which didn't have the rounded nose.
Print with 75 to 100% fill, with supports, 0.2 to 0.3mm layers, PLA prints well but may become brittle in real cold temperatures ABS or Nylon will tolerate the cold much better.
The holes may need to be drilled out if the scale is reduced.
This design requires the use of a wheel collar, 2 is best but a single one will work, and the spring from a small clamp (use smaller springs for smaller skis) for each ski, I have also used the collar from a prop saver.
I replace the set screw in the wheel collar with a 12 to 16mm long 2mm or 3mm screw, only one collar per wheel needs this done.
For a 2 collar setup, put the one with the extended screw on the axel, for a one collar setup just put the ski on.
The spring needs to be bent, put the spring on the axel tight to the ski then put a mark on it, lined up with the front hole on the ski.
Bend the spring 90deg so that when installed the bent end will go into the front hole on the ski
Put the spring back on tight to the ski then put the collar on, you will need to mark the spring again and bend, first a 90deg bend and then a 3/4 loop in the end of it. the idea is to have the loop be able to hold the spring tight to the extended screw.
Once the bends are made put everything back on the axel, the angle of the ski can be set by loosening the collar and rotating it to tip the nose of the ski up slightly, about 5deg should be ideal but hard, rough snow conditions may require more.
Tighten the collar/s and enjoy the cold.
I use http://www.thingiverse.com/thing:88569 to make custom springs to work with these skis