Hi,
If you split in four and still do random positions, you still need to do the math so that they are not to close to each other.
I would use 6 arrays and make preset Raycast positions, so for each index you have a group of 6 Raycasts (6 arays)
Then select a random group index and use for each side (top left/top right/bottom left/bottom right) which would give some extra randomness than using 24 arrays and preset all of them at once.
You might need to use 'world: Self' or use a Vector 3 add, to position for each side.
I also think that preset positions are better for performance.
Btw, i am only suggesting things
Best is to play around and see what fits best for your project.