It is hardly possible to provide usefull information without having
an idea, what you are going to do. To migrate the database for
example you can Install a new Database, modify it with your customizations and migrate your data. Or you can modify your
customized database with the changes in 4.3 (we made it this
way, when we migrated to 4.2).
Different ways mean different problems.
In our case we needed about 4 weeks to migrate from 98.4SP2
to 4.2. One week we needed to modify the database scripts.
The other 3 weeks weeks we customized the VBDs.
We means two programmers.
If you have concrete questions, I will help you as good as I can.