I have written a song that has several tempo changes (stepping from 100 bpm to 120 bpm) and time signature changes (back and forth from 3/4 to 4/4). These changes have been written into the Logic arrangement in the Group Header. The song is in skeletal form and at the moment comprises two au instruments with a handful of apple loops to sketch out the drums. What I want to do, before recording real instruments, is record more subtle tempo variations into the arrangements. Basically the song needs rubato at various points. So how do I play the song, with it's pre-existing tempo mapping, and at various points tap out the rubato so that Logic records these slight variations in speed? Any help greatly welcomed.