I'd like to get some recordings of typical receiver audio output of HF CW transmissions.
I'd like to both train my mental copying capabilities and look into improved automatic (software) CW transcribers; hence, typical, humanly induced symbol rate changes are of special interest. Ideally, there'd be a few recordings of similar (the same?) transmission at different RX SNRs.
Instead of the audio recording, I'd also take "raw" I/Q, IF or direct sampling recordings.
As correctly pointed out in the comments: I'm a total novice when it comes to digesting CW. Which means that I can't tell a well-keyed transmission from a lesser one; I've found it vastly helpful to have reference signals in the past, so I'm really asking for recordings of transmissions of "known" quality, not an information on how to make my own recording (which I can't classify myself).