i measured up how high off the roof the opening under the rail is on each position, then took the roof rack mount i have and centered it up against the cover, marked the edges.. measured up the distance i needed to cut, drew my lines with a dry erase board marker (easily wipes off when youre done) then used the bit bart used to cut away the bulk of the material.. then switched over to this to round it off and smooth everything out


barts method probably works much better when doing more extensive cutting, mine required minimal cutting so i didnt worry too much about making a pattern make sure to test fit your roof rail covers on the roof rails and mark which goes where to make sure you dont cut the wrong cover