I'm in the same boat with my Trillium
, I was doing the same work this summer, I could get the bottom two panes out, but not the top one. it would keep getting stuck because the frame at the top was too close to move the window enough to remove it.
If I remember correctly, with a lot of frustration I did get one of the side top panels out, but I think that is because they are longer and had more room to work, but the back windows
, no way.