I am using PLA+ 99% of the time, testing PETG a bit but each material has its own issues so it takes time to get to know it, for instance opaque PLA+ is somewhat different from translucent even though they both have the same recommendations regarding the print settings. I performed calibration just about a week ago. I sliced the same model with the latest software and with the original which was 1.13. 1.13 came out good but the latest software campout better (various transitions were much sharper etc) but with raft problem so I figured may be firmware which I updated and now its seems to be working fine.
On the the topic of the bottom layer, as I end up dividing models into parts for various reasons I quite frequently end up with printing my models upside down (I do a lot of precise industrial design prototyping) and need more bottom layers to be able to finish that surface - very fine sand paper (600) and liquid polisher.
Also, regarding the printing with raft or without, which gives a better bottom surface I was wondering about a different kind of raft, instead of underlay a sort of collar with a “V” groove at connection to model which could be broken away (much less clean up work tan a full surface). I kind of tested manually this idea but the first layer or 2 have to most likely @ higher temp before going to normal above that.