Pontoons and Centre Sections were both the same size:
25 feet 9 inches by 2 feet 6 inches.
Surviving examples in Canada are very rare as the surplus pontoons were mostly all burned in the 1970s. The example on outdoor display in Petawawa is a post-War Extra Wide Bailey Bridge although the panels appear to be primarily wartime.
I managed to save one of the data plates off of the pontoons which were being burned.