You said "if I partition and install one of these, my Wubi installed
/home and settings are going to be safe, right?"

I think I've mentioned this a time before, but if not, here it is
again: Backup important files in your Wubi /home first. They SHOULD
be safe after your partition and install, but there is always the
possibility that something can go wrong. If you have nothing there
you don't mind loosing, go ahead with the install. Otherwise back up
first. The process to mount and back up is the same from a live CD as
it will be from a new install. As Joan pointed out, if you Use Puppy
for the backup, you can burn the files to CD, or use a USB drive with
any live distro to copy over just the really important things. You
may have already been clear on all of that, but I just wanted to make
sure you were aware there is a risk (albeit likely a small one) if you
don't back up before you begin repartitioning the drive.

Not a bad idea to backup important stuff in Windows, also.

For what it is worth, I have repartitioned windows to install linux on
7 different computers (and more than one repartition for several of
them) and have never had any issue with windows afterwards, other than
having to fix my windows MBR for Windows XP. On the two windows seven
machines, there was no hitch at all that I can remember.

As far as how long the partition and install takes, I would give it
between 20-30 minutes once you have booted to a live CD. You can walk
away, and it will wait for you where user input is required, but I had
a system freeze once that way. So best idea is probably to stay
nearby. If the computer somehow gets shut down during the install
process, you will have to start over.