I dont want to run generator at all and definitely not at night unless grid down HOA with at least 5 acre lots. I will not sell to grid . I need grid for power when solar/battery not enough power. I plan to add more battery in steps to eventually 100kwhr or so. I do not and will not have Net Metering. I also do not want to charge batteries with grid at all. If grid down and not enough PV will use generator. My PV is dc coupled. To be clear there is or is not a NO SELL mode on SBI. Also I looked at specs and didn't see a PV DC input voltage or wattage . It did seem to say ac and array input the same up to 150v and I think up to 56 amp or 13.4 kw.Critical loads panel and load-shed relay is for when on battery and SoC gets low.
I only have Sunny Boys on critical loads panel - the entire house would be load-shed at 70% DoD, but Sunny Island remains up down to 80% DoD so when the sun comes up Sunny Boys see AC and start delivering power.
Eventually I'll shed less important loads like laundry and outdoor lights at 20% DoD. I plan to wire things as (on-grid) OR (> 80% SoC).
You may want separate critical loads rather than running the generator at night. If your PV is AC coupled (Sunny Boy) rather than DC coupled then you should separate them.
I have net metering so Sunny Boys backfeed the grid.
DC coupled PV doesn't backfeed the grid with Sunny Island unless SCC are set to a higher voltage than SI.
I'm not sure how well Sunny Island supports zero-export. So long as PV is less than battery charging plus consumption, you would be a net consumer. I think SI would also suck down power from the grid to recharge batteries faster. Once battery charge current tapers off and you have surplus PV, to prevent export it can disconnect from grid; it would then raise frequency to curtail production.
What you might like is to remain grid connected with batteries floating and PV curtailed to match load. SI can't do that because it uses frequency shift. Possibly Sunny Boy Storage (400V lithium battery) could, because it has a data link to newer model Sunny Boy. But it is featured as working with all GT inverters; for most of those it would have to cycle batteries while leaving the GT inverter on at full output or knocked off line for zero output. Note that Sunny Boy Storage is a wimp, can't power as much or offer the surge capability of Sunny Island.
But compared to Sunny Island plus generator, obviously Sunny Island plus grid is going to be cheaper and less maintenance.
For now going to research the DEYS more.