You can collect a lot of morse code traffic in the wild. Just get yourself a good HF receiver with some filtering (notch filter and a DSP). Set up a dipole as your receive antenna cut to 1/4 the wavelength of the band you will be monitoring. Here is a handy band plan to guide you to where you will be able to find morse code which is normally called CW for continuous wave communications.
I recommend this over any attempt to collect samples directly from hams. I know I do morse code differently when using the radio for casual contacts than I do making exam tapes back when I was a volunteer examiner.
Another attribute that will affect morse code transmission is the type of morse key being used. I use either a straight key which is completely manual and my dots and dashes do vary depending on fatigue, or a paddle key where one paddle makes a dot and the other key makes a dash. The dots and dashes are consistent in duration but the space between them will vary depending on fatigue. I did try using a vibroplex key. The dash will vary in duration but the dots are constant in both duration and time between each dot. Most of my friends still use them (A mutual acquaintance owns the company), but I found myself constantly having to slow down because I would let that pendulum swing speed up my keying.
Happy hunting and 73.