I don't think there is any site where you can download any significant selection of .wav files for the 9960, nor custom group them online (as I think you can for the European models).
Each time you install a .wav upgrade it replaces all previous .wav upgrades, so you need to group together all the setup codes you want into the input of the program that makes the .wav file. Premade wav files are only practical when you need just one upgrade.
The free software from the JP1 group does allow you to create upgrades and group them together and transform the result into a .wav file. But the process is harder than using that same software for its normal purpose (installing upgrades via a JP1 cable).
Since you have so many setup codes to guess among and you can't even be certain that list from the support center is really correct, it would be much easier to work with a JP1 cable than with .wav files.
The JP1 cable allows two way communication with the 9960, so you can learn signals from the original remote and decode them via JP1 and find out exactly what the upgrade should contain rather than guess and test.
If you get a JP1 cable, the 9960 also requires a "pogo pin adapter" to fit the JP1 cable to the holes in the remote during use. The web sites that offer JP1 cables for sale also offer that adapter.