Skip the rom customizer and do everything from safe strap, you'll be fine. Yes, backup that stock room on your stock slot. Make sure to wipe all but SD under advanced wipe, DO NOT format the SD.
If for some reason something happens, which I doubt, it takes 20 minutes to fix via carl's fix.
Flash the toggles through safe
under rom customizer Ota downloads than go to new updates when I download something from there and than reboot than under Ota updates the folder for new updates be gone. Also I been trying to flash alliance theme settings icon I get it to download but when flashing in as it always fail so it's not letting me flash. I'm trying to change the settings icons using that Ota download.