I think this is one of these things that should have a "post-game analysis" of sorts. I don't mean to be critical, but this will be analytical and it may help someone else who builds a house in the future. The idea here is nice, and the essentially linked windows are similar to a true palladian window, with the tall window in the middle and subordinate windows on either side of a height equal to the bottom sash...fine. But you've kind of backed yourself into a design corner because these particular windows need to be covered, and yet you don't want to cover them too much, or all the time. A palladian window in an 18th or 19th c house would be treated like this: The walls would be thick enough that shutters would fold over the small windows and fold back into shallow pockets in the jambs when you wanted them out of the way. The larger window would be elaborately draped because of the curve or possibly mostly left bare,depending. If you were to design this over again---or if your architect does do this again in another house---a peak that was wide enough to allow a single rod or top mounted treatment that was wide enough to cover all three windows completely should be one thing considered, or more room for shutters to be folded back would be another, a shorter or differently proportioned window in the middle another. I think that windows are often designed as if they can all be left uncovered because nobody's windows need to be covered for privacy or light control. And really the opposite is true. Almost Every window should be designed if it will need to be covered for privacy or light control, and if it doesn't great, but if it does you are not faced with several less than ideal options and possibly some really awkward options but no perfect options.

I would just install roller shades in a similar tone to the sheers that you select for the front window for all other windows.

how about you explore other options? wouldn't it be nice to let some light in the room? blinds.com has so many options. I've used them on at least 10 different blinds over the years. Bali/Levolor are two of the brands they use.

I recently bought a product called Veilish. It’s a window film made with fabric material. It’s semi-transparent, so it can provide indoor privacy without blocking the view outdoors. The best thing is that it is self-adhesive, and it can be installed and removed easily, so you don’t need an installation expert. I think you will definitely be satisfied with this product.