I am "testing" unistrut as rails as a C section type arrangement on the cubby house/trust roof I built for the kids 25 years ago. ( the grandies need better ...) The reason was I want the up lift and water problem engineered out . I bought standard rollers off amazon and have ground down 4 so far to 35mm +-0.1mm .They roll ok .The brackets for the rollers only arrived today so I look forward to swapping out the drilled timber blocks .
