OK cool cool.. so what I'm thinking is to backup my whole tablet with everything I have right now in cwd recovery to the SD card... that way if something goes wrong I can install it back....
With these 2 files can I just put them on the SD card and install them from the cwd recovery?
CWM does not support Marshmallow. The DoPa 6 thread has a build of TWRP recovery you can use to install Marshmallow, though- so install that through CWM and reboot the recovery.
Once you're in TWRP, then make a backup. Last I checked, CWM's and TWRP's backups are not compatible.