[Steve R]

Chuck,
Look at the screws that hold the supports on. Maybe they are contacting the edge of the channel that they must go past in order to screw into those flat brass nuts. If that is the case, you could use a dremmel tool to knock a little off the edge of the channel in order to provide some clearance for the screw. Also, I think those brass nuts can be slid out of the channel and turned arround. this might give you the wiggle room you need.
When you finally get around to cutting the side supports to lenth, you will see what I am talking about with regard to the chrome's adhesion or lack thereof .
Steven
PS,
If you are not exactly sure of where to grind, I'll draw a diagram and post it. I am out of time right now and must go to work.....