Yes. Wetting the filter reduces the likelihood of paper flavor in your coffee and heats the vessel or mug you are brewing into.
Always! A 30 second bloom allows the coffee grounds to de-gas before brewing. The bloom enhances the flavor of the coffee.
For an 8-ounce cup of pour over coffee, you'll need 18 grams of grounds. For a 16-ounce cup, start with 24 grams of ground coffee instead.