I need to see the inspiration pic to answer this but I do cornices all the time to house drapes and solar shades they can be built at any time . I will advise when choosing the shades you go dark not white the darker the shade the better the view and in your case that is for sure what you want. I use 10% in either charcoal or bronze depending on you style and colors . As for access the cornice needs to be deep enough to allow the shades to be hung and that also allows for removal in the case of repair. I order my solar shades from Steves blinds and wallpaper have had no issue and the prices are great I would also recommend tht you get motorized ones for cloudy days

Does no one google anything these days!!

http://www.sundecorfabrics.com/Roller-Shades/Recessed-Roller-Shades

Google some more for other companies. The housing is similar to that used for in ceiling projector screens. It sits flush with the ceiling and can be removed for maintenance/repairs.

Yes, it needs to be planned from the start. You can probably still do it. Also add power for motorization/automation. We were supposed to have a large projector screen recessed into a soffit, but the truss company messed up and made the soffit part of the trusses, so we couldn't fit anything in them. We ended up having to surface mount the screen in the ceiling, so not the clean hidden look we had planned.

Inspiration pic. It didn’t post earlier. Thank your for the reply.

From a heat gain standpoint, it would be better to go on the outside of the window. It is hard (almost impossible without a mini) to maintain equal temps to the rest of the house in a smallish room with large western glass at 4pm.

Retractable awnings might be worth looking into too. The possibility of using exterior shades and/or awnings will depend on how much wind you get in the area.

The wind is fierce there. There will be a covered patio but it is not going to be in front of those dining room windows. It’s only May - early September that it will be a problem. But that’s also the hottest part of the year.

Solar/ shade screen on the exterior. You want to block the heat before it gets to the window/ inside.

@patricia colwell consulting - is a built-in valance really necessary for a good clean look? We will have black windows. But white trim. I’m not sure if the doors will have trim around them. If we got a valance from a shade company that was interior mounted in the door opening, what color valance should I choose if walls are a light shade? White with black solar fabric?

I think you need to decide what company you want to provide the solar shade then they will have options . I do not like the look of the cassettes with roller shades and BTW those 10% shades are amazing at controlling heat I have them on West facing widows where the sun in the afternoon is baking hot . My clients all have them since where we live the temps can go to 40 celsius often. have huge overhangs on my South facing windows and honestly the best way to control summer heat if at all possible that would be my first choice for heat control since once the sun is high in the sky we get no direct heat into the house only that one west facing window

The 10% shades on the site are ratedforexterior use also.