Changing my electrical panel

[Saren2]

Hi,

I opened the electrical panel of my house because I need to connect my solar inverter to the panel and got served a spaghetti of an installation.


Made by an electrician in the early 2000's. It's like he went out of this way to not respect any code or national legislation: 1,5 mm2 wires, random wire colors, no dedicated circuits for important appliances etc. (Also no, I cannot break down the walls and redo it at the moment).

Either way, I managed to identify all the circuits. Now, I need to connect my solar inverter to the house. While I'm at it, I'm thinking of also upgrading the electrical panel's content.

This is what I came up with:


My questions are:
1. Should I install an RCBO to the AC input of the inverter? Is a regular MCB just fine? The manual specifies that a 50 A breaker is recommended. Doesn't say anything about any MCB.
2. Should I install an MCB to the AC output of the inverter? Nothing is specified in the manual. I figure opening the DC breaker between the PV panels and the inverter will stop any load going into the house. When I'll add battery banks to the inverter I'll install fuses between the batteries and the inverter, so that those circuits will be interruptible too.
3. Did I wire correctly the neutral of RCD's?
4. Is it fine if I connect with a 5x10mm2 cable between the inverter and the electrical panel? This way I input the AC from the grid into the inverter and output the AC of the inverter back to the house through the same cable.
5. Considering the electrical spaghetti this guy pulled on my house, I wouldn't be surprised if the RCDs tripped. If they do, as an alternative, can I quit using RCDs in the main panel of the house and then put them downstream wherever possible? (garage, tool shed etc). If they trip downstream at least I narrow down the area with a possible fault. I know this is not ideal since the whole house should be protected. Might have to get an electrician do some testing to find possible faults.
6. What's the best way to connect to live both of the rows of the MCB's? Through a wire that jumps from one busbar to the other?

Thank you for your time!