When I wanted to randomise labels in a free format, I would use a constructed list and some SSI Script to assist (by using the ListLabel function).
My constructed list (call it ChoicesConList) would look something like this ...
The ChoicesList is a parent list which stores all your choices.This constructed list would randomise your whole list.
To display the choices in your list, you would use the following ...
ListLabel(ChoicesConList,1) - this will display the 1st item in your constructed list.
ListLabel(ChoicesConList,2) - this will display the 2nd item in your constructed list.
ListLabel(ChoicesConList,12) - this will display the 12th item in your constructed list.
You would need to setup this approach for both the left and right choices. If you are trying to keep the left and right side lists paired so that code 5 in the right list will always appear in the same randomised position as the left list, then use a seed in your Randomize() function.