Ikea kids cups, or the square pots, but yes they remain in them the entire grow, occasionally i’ll repot but i can probably count on one hand how many times ive done that in the last year or two.
Just flopping, which is essentially the traditional method of supercropping but just being more aware of the crush and bend radius of the branches and where you want to place them, also do leaf tucking as you can manipulate what branches sense more light and cause certain ones to either grow past others or at least keep pace while slowing down others
heres an old post about the flopping