Just wanted to post something I'm finding useful, in case it helps.
I keep the latest LTS and non-LTS Ubuntus on my home desktop. Each distro gets a partition for / on an SSD and shares a common HD for /home
I keep the same username for both distros, but maintain different /~ directories so I can keep one set of files and symlink from the secondary distro
The way I do this is to install with a dummy admin account, then immediately create a new account with my name etc, then use the command
Obviously I have trusty and saucy as 'distro' at the moment.
usermod -d /home/distro/myname -m myname
Registered Linux User #407403