Thanks to both for taking the time to reply, this is precisely what I was looking for.
In my use case, I don't need to worry about back-feeding from the critical loads to the main panel; I'm fine with the A/C not being available when the grid is down as long as in normal operation the Sol-Ark...
Thanks for posting this, this is similar to the use case I am shooting for and it's good to see that it may be possible.
I want to limit the draw from the grid to the maximum degree possible during the day, and charge batteries (and run very large loads like an EV charger at night as well)...