You do need to breakin the rail to the can. Mount the rails wider than the can. I do one rail at a time, some lube (dupont teflon), and work it on, off, on, off. A good 25+ times. The rails are harder than the can, and the heat and expansion generated by the on - off will literally shave the tight spots off the can. I get one mated, then the other, then adjust the rails for both at the same time, and it's done. You want it snug, not loose, but doable to start. It is important to get both rails on the can, especially out in the field, of course.
The thin rails also lift the can off the tunnel, allowing snow and cooling to get to the top of the tunnel. Need all you can get with the pro.
The thin rails also lift the can off the tunnel, allowing snow and cooling to get to the top of the tunnel. Need all you can get with the pro.