Hold on! Don't delete those SYSx.MANx data sets!
If you intend to switch from SMF data sets to SMF logging, do not delete any of your SMF data sets - you should retain these as a fallback option. You can just add SMF logging to your SMF data set configuration in an SMFPRMxx member and dynamically switch between recording to data sets and log streams. See Switching between SMF logging and SMF data set recording.