Max content on a conveyor in new conveyor module

The user manual states that the maximum number of items on a conveyor (new module) is determined by the length of the conveyor (and the size of your flow item + stopping space between them).

Working with the old fashioned conveyors, there was an option to alter this and set the maximum allowed flow items manually. What is the easiest way to achieve this functionality in the new conveyor module?

My expected functionality:
- Operator loads flow item on Conveyor 1 if less than 3 items on Conveyor 1
- Operator loads flow item on Conveyor 2 if (otherwise)

Tried to illustrate my desired behaviour in the attached model.