I like the 288 for driver options if you wanted to change it up in the future. But statistically they are pretty close to the same. 304 boards have fv little over 100 volts and max current of 1400ma. The 288 has fv little over 50 volts and max current of 2800ma. So in terms of watts, efficacy, and stuff like that they are fairly equal. They just get there different ways.
And keeping the heatsink together will dissipate heat better, more surface area that way.
One of those kits is plenty for a 2x4, two kits is good for 4x4. In 4x4 it’s similar par levels as having a 1000 watt hps bulb in there.