With my history of mis-behaving install partitioners, you can bet the
farm on that! ;-)
I think the last things I do before starting the install, is to rsync the
currant /home and /opt directories to the new drive I just partitioned
and formatted as ext4. Then I'll have a several hour battle trying to
expunge network-manager and making my networking Just Work(TM).
Then edit fstab to mount the LABEL = /opt drive on top of the /opt
directory is easy. But Jessie will have installed some things in /home
and I am not convinced we have a mechanism/script I could apply to
update the image of wheezy's home on the LABEL=/home partition that will
not at that time, be mounted over the /home directory of the Jessie
install on the other to be main boot drive.
Perhaps that might be another of rsync's talents, only updating whats
different? Man page study time I think. And more caffiene, I'm a quart
low yet...
And one other question: Can the installer deal with a drive that has no
partition table on it? I know for a fact that as it stands for wheezy,
that it will not accept, even if it can see it, another partitioners
partition tables. It absolutely has to write its own table and nothing
a human can concoct will ever suit it. Frankly, debian needs to get an
alaskan divorce from whatever its called and use gparted and be done
with it.