Have you looked at the Cat or Polaris rails? They have no more material but get much taller in the stress areas near the rear scissor. I bet those rails are even lighter than the Doo too?10% is easy...5 pounds. Remove the idler wheels from the center of the skid. And throw a billet rear arm on it to discard the weight of steel. Not much there in the rails. More rail strength will require more material, or better aluminum, which weighs a bit more.
There is no sense in guessing. Weigh them. There are enough people on here to get that done. There are many dynamics to that you are leaving out...type of aluminum, ductility of the material, crossectional design, sled and rider weight distribution, etc. The design must consider moment arm load, lateral torsional buckling, shear, etc. These considerations are for obtaining optimal design, which depends on the rider and sled in motion. Given a fixed cross section, design matters. But, moving material vertically has to come from somewhere, otherwise the rail will be susceptible to lateral torsional buckling. This can be addressed with cross bars, but that comes at a cost of reduced cleaning action in the skid.Have you looked at the Cat or Polaris rails? They have no more material but get much taller in the stress areas near the rear scissor. I bet those rails are even lighter than the Doo too?