I'm sorry, this project was created to specifically show a randomised distribution on a fixed grid. If you want to make one of the distributed objects larger and not have it overlap, then adjust the grid size in the editor.
If you destroy the other grid objects the whole project won't function.
I think you might want to create a new project from scratch to do what it is you are trying to do.
I still don't understand it, but perhaps someone else might.