Set sync to 0.0s, press Play, then press and hold Space (or the TAP button) once for each character as it is sung. On the last character of a line, keep holding for as long as the note is held. The underlined character is the one to tap next. Pick a slow speed for the rap parts. Tap a line in the list to jump back to it.
If the sweep runs early or late overall, nudge sync. Tap a lyric line to jump to it. Timing you record is saved in this browser. Send the copied JSON to Claude to make it the default for everyone.