I'm experimenting with kitchens. If I want to take an updated SYS from Calkulin (2172

, and put it in Juicy's kitchen, so I get Juicy's tweaks/roms with the update sys, how do I do that?
Calkulins 21728 SYS comes with 2 files, SYS and ROM. If i copy both over to Juicy's kitchen, I get an error during the build that a file already exists. Do I just copy the SYS instead of the SYS and ROM from Calkulins file?