- You can not have a fuse between the battery shunt and PV shunt the two shunts will need to be connected directly with nothing in between them and you can add that fuse between the shunt and the positive bus bar.
- Those panels will put out 80 to 90A so the 6AWG may not be quite enough depending on the type of cable on the negative side also the PV shunt will need to be at least 150A rated as shunts can only handle around 66% of rating continues. Same comment about what looks like a 80A fuse after all PV panels are combined.
- The two switches for the inverters can be on the positive side (no reason to be on the negative but it will work the same) and before you are able to close circuit those switches you will need to precharge the inverter capacitors else you will damage those switches. Same thing with the DPST switch you need to precharge everything before being able to turn those ON.
- The batteries because you presumably will have high loads should be installed in a different orientation so that 3 parallel buss bars caries the current instead of just one. Below is an example that is just 4s2p but the concept is the same. There is still a single busbar between cells 2 and 3 in that photo but in that particular case he did not had such high loads like you will have.
-There is also a general thing that you have all sorts of fuses and breakers close to load instead of close to the busbar. Like those 300A fuses for the inverters should be just immediately after the Load busbar as what you protect is the wires and so need to be close to the source (battery) that is an unlimited current source.