When using a plumb bob in a slight wind, you should...

The most effective approach when using a plumb bob in a slight wind is to let the tool hang freely. This allows the plumb bob to find its true vertical alignment according to the gravitational pull. If you attempt to stabilize it with your hand or wait for calm conditions, you may inadvertently introduce inaccuracies, as the plumb bob needs to respond to the forces acting upon it without interference.

Allowing it to bounce lightly on the point can help in ensuring direct contact and can help find the vertical alignment more quickly. However, it's crucial to remember that the assignment of the plumb line under wind conditions generally leads to more consistent and precise vertical readings when left to swing freely, as it will naturally settle into the correct position once the wind's influence diminishes.