Do they have instructions maybe online? I don't think you'd be able to slide from the end due to the curve but if they are that stiff I'd prob cut another slit maybe 60° off of the first and nest the two slits in the "U" part of the bracket.

I'm curious what you figure out.

Oh: before cutting I would try heat. Maybe soak in some near boiling water .

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)