I suggest try both sizes and listen. You should know within 30 minutes to an hour which sounds better. You can always repeat the comparison the next day if you so desire. You do not have to wait for break-in or settling. Vibration and weight will settle them in. You can accelerate the process or use fairly loud music (for a miniscule improvement). Be wise but not crazy with break in methods. Like I mentioned, you will know right away if the footers are right, assuming you can hear the difference. Compare with other footers and be mindful that the platform or shelf material affects the outcome almost as much as the footers.