Great idea

looks awesome

Bunnings do a 750mm long rod as well which works well for the 29" wide type boards as well. See the lower lowest board.

Its also good if you need some extra space between boards after the event because the galvanized end piece on the wall plate can be raised or lowered as required.

I used three galv pipes to support the 14 footer although you need to consider the board rocker prior to putting the middle one in place to get the right height.