You really need both #28 and #11
To make #28 measure the length on your loader where pins (yellow) attach the bars to the loader.
Then Measure that pins length under the hole for clip #29, this divided by 2 will give you the thickness of the bars.
Then go to the loader bucket and measure the pocket height that will give you the bar width.
#11 are square bars they fit into the square holes in the towers (orange).
The length of the short side will be enough that the front tires will clear the bars when when the are inserted in the towers.
The length of the long side will be long enough for the bottom of the towers to clear the pockets.