Use the Assistant for these systems with Solar chargers, where you want to disconnect from mains when possible. Which is the third policy on the list.
Usage of all other policies of Hub-1 have been deprecated, in favor of ESS.
Besides below information, there is more information about Hub-1 here:
No, not anymore since CCGX v1.73. See v1.73 blogpost for details.
The solar charger will charge the batteries until the absorption voltage is reached, and then reduces it's output. It switches to regulation on battery voltage instead of MPPT or output current. In other words: the batteries will not be overcharged.
See previous answer.
With older Multis and Quattros it is unfortunately not possible to feed power from DC back into the grid. It is possible to prioritize solar in a dc-coupled system.
A maximum of 25 units can be connected in parallel.