http://sn.1w6.org/file/mk-20160927T112814-gagyctj.html
Well, #oops. Clearly, I'm not used to the Ubuntu installer. Result: I missed a beat and got everything installed in the tiny partition reserved for root... so I had to re-do the installation a third time. Much better now (and meanwhile I've learned where various configuration options are hiding - at least most of them. ;-) I have to admit I rather like Ubuntu MATE so far! (Thinking now I may install Debian + OpenBox on Dennis, since I cannot update or install anything from LMDE any more since the Mint servers were compromised: So I do need to (re)install *something*.)