Adjusting size of grid cards

My objective - to put a clock and a few entity cards in a lovelace display and use a Samsung Tab as a wall dashboard. I have put together all the objects I require but cannot adjust the grid width so that the entity cards do not overlap the clock.
This is the code I have used for the control panel

  - title: Home
    panel: false
      width: 900
      - square: false
        columns: 2
        type: grid
          - type: custom:clock-card
            time_zone: null
            size: 600
            font_size: 20
            disable_seconds: false
            caption: null
            display_date: DDDD DD/MM/YY
              background: teal
              hands: midnight blue
              numbers: white
              border: midnight blue
          - type: vertical-stack
              - type: gauge
                entity: sensor.temp_vardagsrummet
                name: Vardagsrummet
                min: 0
                max: 35
                needle: true
                  green: 5
                  yellow: 20
                  red: 30
              - type: gauge
                entity: sensor.lallerod_562_orust_temp
                name: Ute
                min: -10
                max: 35
                needle: true
                  green: 1
                  yellow: 20
                  red: 30
              - type: custom:mushroom-entity-card
                entity: sensor.mail_delivery_47496
                name: Posten kommer
                state_color: true
                font_size: 12

and this is the result:

Would really appreciate some help!