I recommend to follow the same way we use in Pharo:
- firstly prepare the SqueakCore and clean it a bit.
- make basic packages like Network and Monticello loadable.
- make the rest of the system loadable using Monticello at once,
ensure everything is working well
- start to improve granularity of that bundle
If I understand correctly, this would mean starting from another (smaller) image than the current trunk, and try to get to the trunk by adding packages. It seems to me that backward compatibility is jeopardized in this process (I know it's not a Pharo value, but it is a Squeak one).
I prefer the process of starting from the trunk and having more and more packages unloadable/loadable (in that order). This way the trunk is always there and backward compatibility can be verified at any time.
Stef