Thats a pretty hefty grow man. thats nearly 4 pounds.
You are going for 1800 grams.
Now for a gram/watt ratio. People that know what the fuck they are doing. Seemingly more than you (no offense).
1 gram/watt is very good. I'd say .5 gram to watt for a few grower or just the average grower.
Now with this said you are looking for at minimum 1800 watts. Safer would be closer to 4000 watts.