the Z-TOP needs a ZWEITE ENTWICKLUNG in the first place
I could think of two versions:
a.) Hatch window needs to be cut (not a good idea) and its frame permanently attached to the top. Rear deck lid with small window needs to be separated...rain water still needs to be adressed
b.) Keep the window size, attach it permanently to the top and build new hinges for the rear deck lid, that would slightly move it around the window, when opened. Rain water still needs to be adressed
plan b would be interesting although the window would reach into the accessible trunk space.