I have 2 pair of 119 and 2 pair 69s, and what is said above is spot on,Just doing a plough now with them on. Gave it a run before I started and was impressed. As Harry so rightly says they are virtually the same width at the back, the difference being the landside edge. On a 119 the top edge of the board is a fairly uniform curve starting at the share to midway down the board. On a 69 the landside edge follows the landside to a sharp point and then changes direction to meet the top of the board at the back, leaving the top and bottom edges parallel from the skife backover, in effect just filling the top corner. The difference is not great but on some soils will prevent the furrow from going straight over the board.
As in all things brightness is all and I would imagine that very much like RWM’s, they will not plough unless Super bright.
119’s are probably the easiest option as 69’s are the proverbial hens teeth. Word of warning. If you do manage to find a pair of 69’s, it will not automatically make you Ray Alderson. It’s not just the board that counts but the main wearing part, the C nut on the seat.
Second word of warning. They can still be beaten by either a bad judge or a good guy with YL’s.