Migration wizards are good if your VFP database is very simple. Otherwise such migration (data conversion) is quite often becomes not a straightforward process at all.

Usually the target SQL database structure does not mirror (and must not) the structure of the source VFP database. I'm sure you don't want to carry into SQL Server any kind of outdated database design.

There is always a need of inserting multiple business rules in the conversion algorithm.

Pre-conversion and post-conversion data validation, as well as logging conversion events all should be parts of the conversion process.

Judging from my experience, a separate custom VFP application and database need to be created for a conversion. The application must provide basic control over the conversion process, ability to adjust settings and the process flow. A VFP conversion database usually is a storage for remote views connected to the target SQL Server tables.