Resurrecting this thread, since it addresses my current concern. I am aiming for two Deye 5kW inverters and two Volta stage 3 batteries. Following the discussion I will ask for the RH side configuration. 

I also want to get this right from the start, so what would you have for cable size and fuses in this setup, <2m cable length? Also, are the equal cable lengths then such a requirement, since the the -ve cables "crossing over" will invariably not be the same lengths as the +ve cables.

No-one going to stick their neck out and give this a go?

I'm going to install 2x Sunsynk 5kw inverters with 2x Sunsynk 5kwh batteries soon and the configuration I'm going to use is as per page 17 of the Sunsynk battery manual, ie. the battery bus bar method, with the exception that there will be two connections to the right to the two inverters. This way I can easily add a third or fourth battery later if needed. I plan to have all the cables between bus bar and batteries to be the same length, as advised on the same page in the manual.