Thanks, Greenfuse, for your reply. It motivated several LOOOONG days of a personal refresher course in disk partitioning which left me even more uneasy about my manual partitioning abilities than trusting to the Ubuntu automatic installer. Finally the lesser of my two anxieties prevailed, i.e., I put the Ubuntu disk in the Lenovo drive, deferred to the automatic installer Guided option to squeeze out some Linux space, designated that space at about 30% of the drive, and "let 'er fly." The install finished about an hour ago and I now happily report that I can boot both Windows and Ubuntu (the first boot of Windows required that Chkdisk examine the reduced Windows home partition), all of the Windows tools that I use are so far intact and working, and, more, I am able to use the Lenovo Rescue and Recover function to backup the home directory to the C:\ drive backup partition, just as I did pre-Linux. That part of the software, by the way (i.e, Ubuntu) is running unbelievably fast!
Short version: Ubuntu automatic installer worked great on my machine. I think this is a real tribute to both the Ubuntu community and Lenovo engineers. And man, I'm thinking I'm really going to like this setup. Next week's docket: wireless networking.