I would suggest not installing a double hung window (up and down type). It would be difficult to reach over the counter to open it. With the measurement you provided an awning window would be something to consider. It opens out at the bottom. The crank is located at the bottom and the locking levers are located lower on the sides. Both the crank and locking levers are easy to reach. Over my sink I installed a 40 inch wide by 30 inch high awning window with an 18 inch fixed transom window above (attached to) the awning window. The total size is 40 inches x 48 inches. The fixed transom window has vertical muntins which match the style of my other windows. I used Marvin windows. Marvin has many style options.

Sounds to me like they make have pressure coming down on them and if so there is really noway to fix this. Are they surrounded completely by wood and if so is the header piece level or bowed down in the middle ?

I would look at white plantation shutters for the windows and a Vertiglide on the slider since you use it every day. I would then either add a cornice over the Vertiglide or some drapery side panels. Now if you have young children I am going to change my Vertiglide recommendation to a vertical. I know no one like verticals but if you have sticky little hands, you want to be able to clean the blind easily! When they have grown to the point where you don't have to worry about that anymore, then you can move to a Vertiglide or something else. Here are some links to a blog you may want to look at for ideas. https://dressthatwindow.com/beauty-of-shutters/ https://dressthatwindow.com/i-hate-verticals-what-else-is-there-for-sliding-glass-doors/ https://dressthatwindow.com/drapery-side-panels-complete-the-look/ Not a perfect example but just trying to give you a sample of the combination of shutters, a Vertiglide and a cornice board. You can really dress up the windows on that back wall to look great! Good Luck!

You have such a nice view I can see why you would want to retain it during the day. I'd mount one rod from wall to wall, and use drapery panels. One panel on each end and wider panels in the middle around the sliders so you can pull them closed. Use a lightweight lined fabric so you can get teh fullness you need without taking up too much space. Don't use shutters. They block a LOT of light even when open, and you would never have a clear view outdoors.