This is the same schedule format that I used as primary chorister. It may or may not work for you, depending on how your presidency likes to run things.
As the children entered the room for Sharing/Singing Time, my pianist would already be playing the PRELUDE WIGGLE SONGS. As soon as I entered the room we began singing them. (If I got there before the pianist we'd start singing a cappella.) This gave the Presidency time to set up the opening exercises and their Sharing Time presentation. It also maintained reverence as the children were immediately involved in singing and moving.
I liked to plan for the same set of PRELUDE WIGGLE SONGS each month. In other words, I would choose about three wiggle songs for prelude, and sing only those during the given month. This gave the children, especially the littlest ones, repetition and consistency.
When it was time to begin Opening Exercises, the conducting Presidency member would give me a signal, and then we would move on directly singing the first REVERENCE song. Next the Presidency Member opened the meeting, and would cue us for the WELCOME song and BIRTHDAY song.
My presidency liked to have another WIGGLE song or REVERENCE song right before Sharing Time began.