I had another idea. As old doesnt change much, why not duplicate the old table and converting the duplicated table ? After we only have to check the changes between the two tables (we could add a flag converted for the current table, so checking is faster).

I think, doing like this we just have to put en down a few hours. Time to convert all tables except old.

And if some old pages were deleted during the conversion. We could check this in background.

Shaihulud