How would you guys recommend displaying a 4' x 4' banner in an interior storefront window? I'm thinking pole pockets on top and bottom with grommets that suction cups can be used to stick to window? Or, maybe there is an aluminum rigid rail that can be secured to top of banner? I'm thinking something similar to the top of a banner in a retractable banner then use suction cups to stick to window. Any recommendations on where to get the rails 4' long? I want the banner to display nicely in the window so it doesn't sag. Also, the customer want to be able to roll it up and transport if needed. Thanks in advance!