I would like to keep only the last backup rotated file with nssm
WriteRegDWORD HKLM $REG_DWORD "AppRotateFiles" 1
WriteRegDWORD HKLM $REG_DWORD "AppRotateOnline" 1
#WriteRegDWORD HKLM $REG_DWORD "AppRotateBytes" 314572800
WriteRegDWORD HKLM $REG_DWORD "AppRotateBytes" 5000