Netspy 12.0 is the latest version of the product. It includes two FMIDS: CC2D66H and CBT2C00.
For the most part, FMID CC2D66H (health check) contains the same modules as CC2D76H (Netmaster 12.1) and CC2D81H (Netmaster 12.2). That means if you include both products in the same CSI you would be overwriting the same modules at a different product level.
So in a nutshell, Netspy cannot be installed in the same CSI as Netmaster if you want both products to function correctly.
It also means that you must STEPLIB the corresponding CC2DLOAD (Netspy/Netmaster 12.1) and/or CC2DPLD (Netmaster 12.2) libraries to avoid module conflicts.