how to install LS DEFROST DUCT

[jhpcat]

Subject car:  69 280SL:  I recall it was a pain taking this thing out three years ago and no I have no idea how to get it back in.  Does the blower fan have to come out no matter what? I have already reinstalled it after rebuilding it.  I hope there is a way to get the duct in without having to pull that blower unit. Thoughts?