I am in a similar boat, here in QLD they have a heap of re-baits for new solar setups, I was considering doing it but we are replacing our roof in the next 12 months so it seemed a bit of double handling and our shed roof is too small for a 5kw+ system. This led me to look into second hand setups, I found a 4yo 3kw system that fits on my shed roof for $500 (everything included, AC and DC saftety switches, mounting rails and brackets, cables. The inverter can handle a peak of around 3.4kw at 20amps.
Its a bargain but the only drawback is the inverter only has rs232 connectivity for monitoring, well I thought so in terms of not understanding serial connections very well. After a bit of digging and looking at the spec sheet I think I could connect a ESP-01 to communicate with my MQTT broker. I have yet to try but am quite optimistic about it.
I am also designing adjustable tilt on the panels using linear actuators and a MCU so that the panels can adjust every week to ensure that they get maximum sun in winter and summer.
Hope this gives you some insight, I will post more once I begin debugging the serial connection and fabricate the roof top mounting brackets.