I've added small improvement in CLI of upcoming RivaTuner v2.23, it will simplify command line based programming of VRMs on SLI/CF systems:

- Improved command line interface. Added /SG and /SELECTGPU command line switches allowing selecting tweak target by GPU index rather than by logical display device index represended by previously available /SD and /SELECTDEVICE command line switches. New command line switches are supported for both queued hardware access scripts and for command line based GUI device selection changing.