Small to moderate. You want to be on the North-East coast for the best surf.

First, make sure you have Surf, and it's taught to a Pokemon in your party. Then, go to Olivine. Go to the west coast. Surf down past the Whirl Islands, then head west again. Keep going until you get to the coast. You're now in Cianwood.

The area of Surf Coast Shire is 1,560 square kilometers.

Yes you can but the only really decent waves come when there is a storm/hurricane on the way. East coast is noting compared to west coast or hawaii or Australia

The West Coast can indeed see meteor showers in areas where there is little or no light.

However, this is very rare due to the countability that meteor showers occur rarely.