I repeat....

Try gluing on a piece of cardboard to expand the width to that which it would be when a full size drive is there. Close the case. You prubably will experience difficulties closing it. When you open it, if you closed it fully, you will find your cardboard is all out of place. If you put wet red paint on it, you would find your RAM covered in red paint.

Don't bother cutting. It won't work.