It is a hard choice.
Not to make it more difficult but one other consideration is how much coverage you will have for the area between the two side-by-side windows. Meaning, if you choose two separate shades for the attached windows, will someone on the outside be able to see in if they stand at an angle? That isn't as much of a big deal for 2nd and 3rd floor windows but you may want complete coverage between the two windows on the ground floor. On the other hand, the ground floor windows may be when you want different heights for opening and closing, too, especially if you have the windows open to catch a breeze.
I don't think there is a universal best answer. I think there is the best answer for you. And what you do on one set of windows may vary for the other windows. I know I usually want all of my windows to have the same treatment but there are times when you'll have to make a different choice.