Man that box will not be able to handle the Diesel Auto size, take a look at my diesel auto in my diary, just to have an idea how big she will get. You will probably will need more watts in there, as rule of thumb if you veg a plant with X watts you will need 2X in flowering. Take in mind that the buds will loose about 75% of their weight after harvest.
Take a look at this video www.youtube.com/watch this guy knows what is he talking about.
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