I'm trying to install a full width alcove bathtub sliding glass door. Problem is the width of pre-built tub doors, especially those at budget price level such as this one, seemed to be standardized at max 60" but the width of my bathtub and alcove is 64".
How to address the 4" shortage both cost-effectively and aesthetically? Presumably I am looking for a commodity product preferably available in local hardware stores to fill the gap. Example product link would be helpful. I have thought about using U-shaped aluminum channels but most channels are under 1" width. There are high-end or custom-built tub doors fitting 64" but they cost over $800, which is over my budget.