@bolchisb
My first battery pack came with 35qmm silicon cables. Later once have been upgraded to 50qmm after complaints from community and famous YouTubers like Andy from OffgridGarage.
I have a Lynx Distributor as DC bus bar in between batteries and MP2s. The name Lynx is used for a range of Victron products only one being a BMS.
See my build thread about more details one fuse monitoring and alerting.