Row Block - Mobile Layout/View should allow custom flex/grid container widths (Request)

Please allow the row block for mobile view to have the option to drag the width for columns. At least for 2 columns, you can only choose 50/50 and 67/33. It should at least have the option for 65/35, 60/40, 70/30, 75/25, 80/20 splits without having to use custom css. Thanks!