Waht is the reason for them at all? Please post a pic of the house from further back I love the look of drapes outdoors but IMO they add a whole new level of stuff that needs cleaning all the time . I prefer white or cream to any print and I still like Sunbrella for outdoor fabric.

West facing opening allows too much sun in summer and for romantic effect

I've only ever used Sunbrella outdoor cushions. They did not clean well. I would get a solid color and one that will hide dirt well.

I understand the desire for a romantic effect though. Perhaps you could use an outdoor roller shade for blocking the sunlight and then just a minimal amount of outdoor frabric gathered at the posts for the romantic effect?