I’m thinking there were some posts from this site that were lost when this site went down for a little while and then came back. There was a French person who commented about the spider system on here. I think I remember him saying that the sliders added more flotation in the deep snow. About 50% for the middle replacement of the two wheels and about 75-100% more flotation with the front 3 wheels replaced with a slider. You are sacrificing ride comfort and more noise for the better flotation in the deeper snow.
There is a Facebook page from Quebec called “Les amateurs d’autoniege/snowmobile du Quebec” where they show all their bombardiers and the various slider systems they use.
Some use wood for the bottom slider, others look like they are using a UHMW material I would think.
From what I see when you use the longer slider, two of the axles are in a pocket where they slide back and forth for tilt movement.