architecture and DIT change strategy

Hello.

I'm trying to find the best way to conduct a consequent change in our 
data model and servers topology, with the fewer service disturbing.

Before the reorganisation, we were a single entity, splitted on three 
different sites. As a consequence, we had a single database for all our 
users and groups:

dc=new,dc=foo,dc=tld
|-users
|  |-site1
|  |-site2
|  |-site3
|-groups
    |-site1
    |-site2
    |-site3

The master server is hosted on one site, and we have slave servers on 
three sites

After the reorganisation, we are three different entities, and I'd like 
to break the tree in the three different databases, each site hosting a 
server acting as the master for its own base, a slave for the two others:

dc=site1,dc=foo,dc=tld
|-users
|-groups

dc=site2,dc=foo,dc=tld
|-users
|-groups

dc=site3,dc=foo,dc=tld
|-users
|-groups

The change also involves dropping the last part of the original suffix, 
which is no longer relevant.

I'm currently investigating the usage slapo-rwm to provide virtual views 
of the current database according to the new structure, so as to 
progressively migrate applications configuration first, then write an 
automated conversion tool, and finally convert the virtual bases to new 
ones. But maybe they are better strategies ?
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