@JM58 the sun is free !! You can't beat that !!
In general I'm sure your free solar is best used during production for whatever you can in the home first, as usage tariffs are far greater in cost than whatever FIT you will get.
With solar only, self consumption is far better than sending production to the grid for a usually very low FIT return.
There are some limits you should watch with inverter size.
If you use MORE than you inverter capacity, it will only let you use the inverter KW limit in the home, before drawing from the grid, for example . . .
If your inverter is 5kw, and you use the washing machine, dishwasher, have an air cond on, and are perhaps using 7kw, you will be drawing 2kw from the grid.
Usually this will be in the cheapest tariff time shoulder during solar soak, but still, you are drawing from the grid.
You'll still save a heap, but if you stagger that use and keep it under the inverter limit, it's better.
Having a 10kw inverter is usually enough to eliminate that for most home situations.
If you have a battery too, this negates the need to think about a lot of those requirements, but you just have solar from your post ?