[Samba] Best procedure for migration?

[Sherwood Botsford]

Looking in both Samba3 by example and in Samba HowTo has come up 
empty. There is a chapter in Howto on migrating from 2.2.8, but 
it mostly describes the changes in 3 from 2.  Nothing on best 
practices on how to do it.

I have two servers running samba 2.2.8a. on FreeBSD 4.5  I have 
two new (new to me anyway... 2nd hand netfinity boxes) running 
FreeBSD 6.1 along with a fresh install from packages of samba 
3.0.21b.

Now I have a task that I think is akin to changing the spark 
plugs without turning off the engine.

Q1.  Has anyone produced a guide on how to migrate samba 
gracefully to another machine?

Q2.  Is it a bad idea to couple the machine migration along with 
the samba upgrade?

Heres how I see the problems:
1.  Move files.
This would be done using rsync, so that the new server would 
remain consistent with the old server.

2.  Move unix logins.  Fairly easy.  The PDC is also the YP 
server.  Make the new server a ypslave.  Later we can reverse the 
two roles.

3.  Move the samba logins.  Initially do this by copying over the 
  smbpasswd file.  Later convert to LDAP or TDBsam.

Now it starts getting tricky:
What do I need to do so that the new server appears as the PDC of 
my domain?

What do I need to do so that the users don't notice the switch.
At present there are a whole bunch of shares that are mapped via 
a logon script.  The shares will map the same way, except that 
\\conan will be replaced by \\peon.

What happens to memories of the old shares?

I'm sure there are a million gotchas in here.