yes 7 litres all the way, we usually start in 1.5 litre pots and transplant to a 7. Maybe the plants will get bigger without the transplant but we will see.
the idea is not to have space ,
to me a vacant space is a place there could be a bud
we will just adapt as we go along, some defoliation may be required also some lower branches will be snipped.
to feed we will remove the plants and water a row at a time whilst putting them back in, it gives chances to organise, inspect and rotate plants.