i would use a tray 4x4x8 and plant them all equidistant

but if other wise i would run them in one gals or 1 1/2 gals and go for deeper over wider youll get better bud production

but in one gals i get more bud from a 400 than a geezie (1000w) cause there is not enough root space

the 3 in 3 could work also each plant still gets a gallon+ and if your going clone to flower sog you have time b4 the roots entangle just remeber to feed each plant individualy and dont soak your soil about a cup every other day unless needed and keep them single cola