Tips: make bus bars to carry your 12V power to the batteries and to devices. You can have a fuse at each device connection within the bus box. This makes things better lined out and eliminates a lot of wiring confusion. Your monitor shunt should be between the battery's negative phase terminal and frame ground. You have the ground bus bar depicted but not the actual frame to ground. Also lacking, negative 12 V phase to battery and negative phase of different devices. Think about installing a disconnect switch between positive phase battery and distribution. You may install things like alarms, radios, and circuit boards of devices that like to sip power,even when "off". The disconnect switch eliminates battery drain from those parasitic loads.
Here is a picture of a DIY bus box that I made using a conventional plastic 4" exterior grade junction box and copper bar stock:
