Interesting question.
I wish I could impart my wisdom, but I have to confess that I chickened out and gave the job to Life's to do when my car was serviced.
They did a great job with the 'tweek' and now the side screen sits against the foam pad on the windscreen frame with just the right amount of pressure, so all is well.
But I have no idea how they did it without marking or twisting the bottom slide rail.
