Scratch

I think broadcasts are exactly the right synchronization method for projects like yours. Another way to synchronize sprites and scene changes would be to use the timer. This works well in (simple) animations with fixed time intervals, but won't do in interactive projects relying on user input to trigger events.

You're doing just fine, keep up the great work!

I think that broadcasts are the correct way to synchronize events between sprites, and are even useful for synchronizing within a sprite.  I use the timer very little—only for those things that need a specific time, rather than coming after some other event.

For an animation, I usually create a master script on the stage that consists of a series of broadcast and wait commands, one for each scene.  Scene scripts may include other broadcasts, to do specific actions that may be needed in multiple scenes.

I used the timer for the "Smooth Glide" demo (http://scratch.mit.edu/projects/kevin_karplus/68800), since the goal was to provide a glide with a fixed time.