The speakers configuration should correspond to what is selected in SimShaker Sound Module as number of channels. As close as possible.
1 channel -- Stereo, since Windows doesn't offer us Mono
2 channels -- Stereo
3 - 6 channels -- 5.1 or 5.1 Surround.
If you operate more than 2 shakers, I'd recommend to use the latest version of SimShaker Sound Module which is 2.35 beta at the moment. The main reason is that ASIO driver usage became optional. Most likely 2.35 will be the next released version.
Basically, you can keep both released and beta branch versions at the same time. There may some backward compatibility issues be encountered in the settings, since both branches share the same settings file, but usually they are not mission critical.
But within one branch I'd recommend to always uninstall previous version before you install next. Microsoft installer which I still use is not perfect.