MFL thanks for posting this question as I learned something new today.
While it's not a Champion, the procedures are probably universal. On my Honda eu2000i I have always started the generator and let it run on choke for about ten seconds then slowly turn the choke off. After the generator seems to be stable I plug in the shore power cord. I don't think I've noticed much sparking and many times I'm plugging it in when it's dark outside.
For shutdown I typically just turn it off then unplug it.
HOWEVER, I just read the owners manual while I'm typing this.
Page 33 (Starting the Engine)
Step 2. Make sure that all appliances are disconnected from the AC
receptacles.
Page 35 (Stopping the engine)
To stop the engine in an emergency, simply turn the engine switch to
the OFF position. Under normal conditions, use the following
procedure.
Step 1. Unplug appliances from the generator receptacles.
So it seems that I've been doing it wrong all this time. One thing I did note is that nowhere in the manual does it say to plug in with the breaker off and then add the load. I can see the benefit to plugging in with the breaker off, but the manual definitely does not touch on that subject.