First server migration

How's this for my "plan"?

Rather than upgrade my DS Master box as the first server (since it's
also the CA and runs IDM 3.5 on it), I was thinking of going this route:

1) Upgrade DS Master and the other two R/W replica servers to eDir 8.8
SP2 (they're on NetWare 6.5 SP6, so that would also mean upgrade to SP7
and then do the eDir upgrade)

2) Take one of my other file/print servers that's in that tree and
upgrade it to SP7 and eDir 8.8

3) Then do a migration of THAT server to OES2 Linux and just mount my
existing NSS volumes on the new OES server.

From my reading it didn't seem that I had to upgrade the DS Master box
to OES 2 Linux first.

I'll have like 50 other servers in the tree at eDir 8.7.3.9, so I hope
that will be okay.

Any thoughts?