I'm in Lake County and did DIY off grid with roof panels, I used Greenlancer online for my plans sets and engineer drawings. I filed the permits myself and dealt with inspection. Was not too bad in the end.
Just be organized, know exactly what you want, hardware and specs upfront. Be ready to purchase any outstanding hardware immediately once approved as your then bound by your plans. If your solar panels go out of stock or EOL / Roof fixings you chose are not available you will have to file for an addendum and change your plans to submit addendum. It all costs extras.