I grew them by not topping or training them and removing most side branches.
The more you top or lst your plants the more bud sites you get, but they will be smaller buds.
You do need good light for you space, You need tight internode spacing so the bud will fill in full. those were grown with 2, 400 watt HPS, in a 2x10 closet.
There are some real drawbacks to growing buds that size, first it takes a lot of ceiling height because they will grow tall not bushy fast.
And so easy to get bud rot deep inside the buds.
Some strains just grow bigger buds, These are Dutch passion WW