Final Cut Pro 10 Change clip appearance of some clips in timeline
I am pretty sure you cannot change the clip hight for a certain timeline independent. What might help a bit is when you give your stacked clips different Roles and then click the 'show subroles'. What will move the audio to the bottom under the main timeline and will leave you with the clips only. Now click the 'Focus' button for your main timeline. Then all other audio tracks will get minimized to a narrow line. However, this does not help with the clip high.