trike gear on skiis is a challenge, you need hard enough snow to support the plane. whereas an overpowered tail dragger is a blast on the snow, sinking in doesn't matter as it can pull it self out vertically anyway. (the pic below was hard crusty ice snow, I think i spent as much time cruising around on the ground as i did flying!

as far as the dubro skiis, i've seen people install the springs both ways. the way I prefer is to let the ski ride up in the front, and set the neutral angle to 5 or 10 degrees up also. this helps the plane stay on top of the snow much easier.

[link=http://www.ryankramer.com/planes/images/se2.jpg][/link]