(5) Lower target volume for all tracks as much as required to avoid clipping:
What some members are requesting. The drawback is that the tracks would become too quiet to playback normally in popular/cheap/low-powered players and machines. Also, you would have to do it all over again whenever you get a new clipping track, targeting an even lower volume, not to mention asking Steven for the support.
This.
Personally I am taking a lot of effort to prepare my collection tag-, art, and sound-wise, and would not need auto-adjustments or any kind of limiters afterwards.
If the slider could be have a max. attenuation of -9dB instead of current -6dB it would help users who care about their classical collection, and are willing to take the same effort.
With this available setting at least 99% of all albums would be covered. I don't believe Steven would be bothered for the remaining exceptional cases that can then be edited manually. (but in case he is, make it -15dB while at it)
Also don't forget that classical music is a whole different ballgame. Not only in tagging, but also in 'loudness'.
For a lot of classical music even -9dB album gain is not 'too quiet', but it's just correct, and necessary for well tuned audio equipment of good quality.