Configuration for Cosy Octopus

[bjtallguy]

Q: Can anyone please help me configure my inverter to charge during Octopus "cosy" cheap rates?

I want to write a simple guide for the community and therefore need to actually understand what I am doing, not just that it works.

The kit:

Solis S5 hybrid inverter
XXX 5kWh battery
12 x 435W (5.22kWp) panels (mix of East and South facing

HACS modules installed:

 Solis Cloud Control Integration
 Solis Cloud Monitoring
 I do not currently have a modbus feed configured and want to avoid if possible

The questions:

Where can I find the current battery SoC? percentage
Where can I find the current battery rate of charge / discharge? kW
Do I need to update the inverter clock to reflect summertime rate changes (Octopus rates are current UK time, rather than fixed)?
What do people do to ensure inverter clock stays current (mine appears to drift)?
Can anyone explain the following parameters - and what should I set them to?:
    Battery Reserve (switch)
    Allow Export (switch)
    Battery over discharge SoC (percentage)
    Storage Mode (Self-Use, feed-in Priority, Off-grid)
    Allow Grid Charging (switch)