how do spiders manage 2 spread silk from on leaf to another that's a good few metres away?

Answer 1

They can climb higher and fall across - being so light the slightest wind can carry them across quite a distance.

They can also attach a thread from which they can swing higher up - if available - and simply swing from one side to the other.

Once a construction thread is established, the spider can dart back and forth to run other construction threads before the main web is built.

Answer 2

They swing themselves on a thread they are spinning out. There is no limit to the new thread's length so they just have to get their little bodies into motion (and may be aided by the wind to drift them over to where they want).