Thanks for your response... 

I've got a watch-only wallet which shows me the addresses with coins on Windows so I know which ones I need to sweep.  (I took a photograph with an old camera to record those). 

Then I'm going offline, on Linux, generating my wallet from seed. 

First thing I did was increase the gap limit to 200 and that does not add new change addresses to my address list, only regular addresses.  Offline, there is no record of usage or coins at each address, of course. 

As I posted, I've also used create_new_address, but it's yet to create those few change addresses I need.  I generated about 200 already and am searching for the address with a text editor. 

Sorry to confuse, I meant to ask, in the second question, why I couldn't type a public address from within the console to getprivatekeys().  Does Electrum really need to 'generate' them to see if they're mine and that I have authority to see the private key?

Thanks again for your help...