Here's one area.  If I put a wall panel below the cantilevered roof panel, the top edge of the wall panel projected above the beam ad prevented the roof from lying flat.  Therefore there was not enough space to install a wall panel just above the roof.  It seemed I could have one below or one above, but not both.

 

I considered cutting a roof panel to fit, similar to the way a wall panel sometimes needs to be notched or trimmed to fit...

An easy solution turned out to be installing the lower wall panel on the inside faces of the columns, rather than the usual position on the outside faces of the columns.  That way, the projection of the lower wall panel was beyond the edge of the roof, the roof could lie flat, and the upper wall panel fit perfectly above the roof edge.  (Of course, the lower wall panel must be a notched one, but I had several on hand.)

 

Upon close inspection one can see the difference.  But when the column color matches the roof panel color, it's not very noticable, especially because it's pretty well hidden by the roof from most angles.

 

This technique (or a better one) may be nothing new to you, but it was fun for me to discover it when I needed it!