I also made a tool from an old hacksaw blade (you need heat to bend it) but wound up taking the glass, with the lower channel attached, along with the wing or vent window, with frame and all, to do the outer. It maybe took longer but was less frustrating doing it that way. Tool not needed with the glass out.
The glass and vent assembly can then be worked back in, once you get the right combination. Finally the inner seal goes on from the inside with various tools and levers, a screw driver handle for instance, pushing the little clips on.
PITA but I could never get the clips on with a tool. Probably just me, as I think many others have done it.
Either way, make sure you have a magnet to get the dropped clips out of the bottom of the door.
Tom