When I make a new variable array in the WE GUI, it lets you pick a size, but does it matter? I just left the size at 1, but I could still use array[1], array[2], etc.
The size of all arrays is always 8192. The thing GUI calls 'size' means the number of indexes that will be initialized during init. For example, if you set the size of an array to 13 in GUI and the default value is -1, then all indexes of the array up to the [13] will have -1 initially. The other indexes will be 0.