Thing is, panels are so cheap that if you put them on your roof, it very well might cost the same or less as roof tiles per m2.

You can also put more panels on than the rated peak of your inverter. As long as you don't surpass voltage limits, if you put on more panels, youll get more generation during non-peak hours, and it wont even affect your inverter negatively.

Usually you can easily put 2x+ the peak wattage, as your inverter likely has 2 strings, and each of them can take the whole capacity of the inverter alone.