On the subject of blown canopies, I believe in the UK, the largest single skin canopy was the DH Hornet one that was first made in 1944. This was roughly 7 feet long, 2 feet wide at its base, and roughly 2 feet tall! Clearly they had a few teathing troubles, because several early were reported to have ones shattered in flight.

…. see my AVATAR for a piccie.