Welcome! You chose wisely with the lighting and nutes.
Your choice of a 2 X 4 tent is really more suited to one plant unless doing some advanced growing techniques. In fact; I have one plant in just that footprint.
There’s my journal; just scroll to the end if interested.
5 gallon buckets are problematic with DWC simply because they don’t have enough reserve capacity so you end up chasing PH issues in flower and have to top up the buckets sometimes twice a day. I’ve had plants consume better than a gallon per day and when you only have 3 1/2 gallons of nutrient solution it can change drastically. (5 gallon buckets with net pots only hold about that)
I would advise one plant, pick up one of those yellow-topped totes in like 20 gallon or so and use that. Just run one plant in the 2 X 4 to see what your challenges are.
You will also have issues with maintaining proper temps in the buckets/totes. You really need to be below 70F to reduce the chance of root rot (pythium) and to properly oxygenate the medium. A chiller is the best way to maintain temps. It is an expense and sits outside the grow space but is invaluable.
Hope this helps a bit. It’s fun to grow this way and amazing root mass. Depending on strain you can get some fast, heavy yields this way and it’s a very clean smoke too if you run em out well.