Can someone who has easy access to the bed stake pockets confirm both the opening dimensions Width, Length, and how far vertically from the rail surface can one go down before hitting the sides of the bed?

I've been thinking about installing something to pop up my ARE shell for those times when the cargo fit's under the cap, but won't fit in through the opening as the glass doesn't go all the way to the top.

I don't know if it does or doesn't matter, but I have the 8' box so I'm most interested in that option.