I'm not sure exactly what you need help with. Also not sure if you're interchanging blinds with shades. Only shades can be made top down bottom up.

I guess I'm interchanging. I want to order natural fiber shades, lined.

the window is 146" wide, divided into 3 sections: 38.5", 69", 38.5".

The smaller sections on the left and right sides slide to open the windows, and I wanted to only have to open the shades that correspond to those windows to slide them open and not have to raise the center shade, but maybe with outside mount as long as the divisions are close to the locks that would be adequate?

I thought that if the lock mechanism was exposed when I raise the smaller shades I could slide the windows open without adjusting the center shade.

thanks!

I think I understand what your saying, just measure to the mid-point between the panes.

My drawing isn't that great but these windows don't have trim; they are previous owner replacement windows in a 1960s ranch, meh white vinyl, so I was trying to draw the vinyl frame around the panes. otherwise they are just drywalled with very minimal stool(sill?)/apron.

Thanks for the advice!

Yes, then to the mid-point between the windows. I think you'll be happier with that look.

Also, I notice some of the online companies recommend you extend out 1 1/2" on each side of the window to block more light, but personally, I think that's too much. I wouldn't go more than 1". Again because it just looks nicer. : )

Just updating that I ended up having to get three separate shades... window exceeded the 3-on-1 max width. I can raise the center shade and access the sliding windows on either side.

Glad the options worked in your favor. Hoping to see the results and how it looks. Trying to find solutions is always tough.