I have two mobile stands for laundry hanging, both occupy the same floor space. The difference is that one of them has half the number of clothesline wires (denoted hereafter as "the sparse stand").
Another fact is that I prefer avoiding clothes clips, because they leave marks. This means that I hang shirts, for example, by folding them by their armpits.
The optimization goal:
Having the laundry dry as fast as possible. The exact optimization goal is not the makespan (the time difference between hanging the first item and removing the last) but rather the free clothesline wires. To be even more precise, the time in which there is enough free clothesline wire length to hang another washing machine (this is weekend washing - lots of accumulated laundry or once-a-week machine loads). This is a micro-goal which should lead to high laundry throughput during the weekend.
The free parameters:
I can choose where to hang laundry by the length of the items. Hanging long items on the sparse stand, short items on the dense stand, will bring to an even distribution of moist in the air, because the long items contain more moist, but the sparse stand has less wires, so the moist division is more or less even. This may lead to many items drying together.
I can choose, on the other hand, to hang the long items on the dense stand. Long items can carry their weight without clips even when they are not balanced over the wire (e.g., a large shirt hanging by armpits). Short items must be hanged by their middle. Folding the small items in half creates a high density of moist in the upper part of the dense stand, and the air flow is impeded. the small items can hang on the sparse stand without touching one another, while the long items touch one another only a little, even on the dense stand.