On earth, a photovoltaic solar plant producing about one 1 GWh per year, will require around 2.8 acres of land. The moon has no atmosphere, so a 300-watt panel on Earth would produce 400 watts on the moon.
A GWh could be produced using 2 acres of land on the moon. An acre is 43,560 square feet (180 feet X 242 feet). In the SpaceX picture, it looks like they have solar panels on 200 acres. This would be about 100 GWh per year.
A rule of thumb on earth is 1kW per 100 square feet. On the moon with higher efficiency panels and better sunlight it could be 2 kW per 100 square feet. 200 acres would be about 170 megawatts. This could be 200 GWh per year. If the moon base solar power was six times bigger then it would be over 1 gigawatt of power. This would be 1200 acres or just under two square miles.
The system could weight 1 kilogram per kilowatt. In 2015, space-based solar power was 6.7 kilograms per kilowatt. The weight efficiency is being improved and simple lunar materials could be used to make some of the structures. This would mean transporting 1000 tons of material for a gigawatt of solar power on the moon. This would be ten refueled Starship landings for the main solar power systems and another five for construction machinery and other systems. There could another five Starship landings to provide batteries.