Cable Sizing for AC connections and Battery Connection

I have an 8KW Deye Hybrid Inverter with 2 x Hubble Lithium AM2 Batteries 

I am placing my installation about 30m from my main DB in my newly built garage. I have a new DB installed there a bigger one. 

My installer recommended we place a 4 core armoured 10mm2 cable for grid and non essential connections, we have a 10mm2 cable for earth seperately . this is a 30-35m cable run between the main DB and the inverter / new DB in the garage. Cable Run is in trunking and in the ceiling 

the 10mm cable I believe to be within SANS spec to accomodate max current from 1 inverter. 

I do want to add 2 more inverters in the future . 

Now I am not sure if i understood the installer correctly but he says we can run 2 more 4 core 10mm2 armoured cables to accomodate the current from the 2nd and 3rd inverter . 

Is this the correct way of doing it ? 

Because i read that a 50mm2 cable is required for the max current output from 3x 8KW inverters.  Honestly i dont know if I understand this correctly. 

Guys with 2 or 3 8kW inverters what does your cabling look like from inverter to AC essential loads and grid ?

For the Battery side I used a calculator i found online, I need a 70mm2 DC Cable to accomodate the max 190A charge/discharge current from the inverter (approx 2.5m cable run) , the batteries are rated at 105A and 48V, actually i am not 100% sure because they changed the spec it used to read 100A and 51v . If I upgrade to 4 or 6 batteries in the future , i am assuming i will have to upgrade the battery disconnector and all the battery cables ? DO I use one battery disconnector for each inverter or is it just one battery disconnector for all 3 inverters ? Going to be using a 200A fuse on the disconnector for the one inverter. What spec for cabling and disconnector when upgrading to 2 or 3 inverters with 4 or 6 batteries respectively ?