What size pot?

w80xl80xh160 got 5 seeds want to grow them fast and efficiently would I opt for 3 gal or is there a narrow enough 5 gal probably looking at a sog method only growing to 50-60cm high in veg

In my opinion, 1/2 gallon to 1 gallon is plenty. Flip them to 12/12 on or around day 24 counting from the day you get the seeds wet. They should be around 3 to 4 inches at that point.