Several years ago I made an attic windown quilt and didnt fussy cut but rather just cut into the squares required for the size. In the end I didn't really notice that it was not fussy cut. It was an all over jungle scene.
I then did what I call a "Mock Attic Window". This means I didn't cut the sashing for a mitred corner but rather folded over the end making the mitre. It went together really fast. I didn't close the fold mitre but probably should have. I really don't feel that you need to fussy cut unless the pattern is one that might require it. No one has evern commented on my cutting the tails of the monkeys off. After all, if you look out the windown you are going to cut some of the scene at the edges of the window frame.