Resize array in script not changing in the inspector

Hi, I have around 300 arrays, and in my script they were all originally set to a size of 10, so in the inspector I've always seen the 10 slots, now I want to resize them to 20, but when I change the values in the script to 20 they all still only show 10 in the inspector, is there a way to force the change in the inspector instead of changing each one at a time in the inspector? I know once you add a component to array, Unity serialises it and no longer cares if you change the size of the serialised array in the script (unless you click on the gear in the inspector and reset it) but as I want to change the size in script the "Rest" in the inspector is not an option. Thanks.