Congratulations on your progress and your new to your radios, both new and used.
I have had a number of 7950s back in the day and they worked very well. The only thing I ran into is issues with printed circuit board connection failures due to the heat produced by the final RF power amplifier section, simple fix.
If you are not already doing this, spend some time listening to you local repeaters. This will help you understand the sometimes arcane operating practices employed by some.
And by all means continue your study for the higher classes of license.
My first rig was a DIY single tube CW power oscillator transmitter (with all of it's inherent instability
) and a DIY receiver.
Your CW key is what is known as a J-38. There are special events set up on the HF bands for the use of a straight key as they are known. Then there are mechanical keys known as bugs, that will make and complete a series of dits and dahs. The next step is what is called an electronic keyer, that forms the dits and dahs electronically and may even contain character memory.
Good luck with the tests.