What are you using for a hood? Is it aircooled? You dont really have to have a bucket with a rack, its a good idea, but probably a waste of time. Just put the plants IN the try, and use the extra space.
4 per SqFt is 64 plants, its manageable, but that is a lot. They are going to get packed tight depending on the growing style, and under the 1000w light they are gonna get big fast. Depending on the strain, the small pots could become an issue.
Are you worried about odor? Cooling and humidity is a MAJOR factor, everyone always overlooks environment, but it can increase yields a lot.
You going to need an AC or else a cold air intake for the winter (AC will be required in the summer)
Humidity is important, especially on tight SOG grows. Make sure you get air moving above and bellow your canopy, and its a good idea to have an inch or two between the pots for airflow to the roots.
Your on the right track, but you should start looking into environment, air flow, cooling, odor. You literally need to take control of the airflow in the room.
Like at my place, every time I open my grow room door air Only rushes Into the grow room, never out. I keep a slightly low pressure in the grow room so theres never odor leaks. The low pressure also gives me the option of bringing in fresh air at any time without fans, I can simply open the window and air comes rushing in.
Yeah depending on the strain your growing, I would at least start with 1 gal pots, see how they handle them. I seriously suggest taking out a tape measure and laying out your grow area, lay out some empty pots to get a better idea of just how big it really is. Things always seem a lot smaller in your mind once you start laying stuff out you can really get a hood idea of whats going to work for you.