First off, this will probably takes months of rehersal depending on the size of your application. Data may not translate cleanly over to SQL Server therefore exporting data to text files may be a viable alternative in order to get a successful import to SQL Server using BCP.

Second, don't disregard the wizard completely. The wizard might be able to get most, if not a good chunck, of the scripts necessary to complete the upsize. You could at least use it to build your SQL Server Database and refine it as you see fit.

Finally, practice, practice and practice your routine for upsizing - the day you switch over you'll be happy you did. In fact, you may want to setup a staging ground in order to practice the whole routine when you're ready to upsize your data.

I remember upsizing about 16GB of VFP data. We had to modify the application in places where we used dynamic queries, setup views on SQL Server to immulate Views in VFP, translate VFP Stored Procs and modify VFP Views to point to the SQL Data instead of the VFP Data. Finally export VFP data to text files, create the mapping files for newly created SQL Server Tables.

I think it took a total of 3 months if I'm not mistaking but the weekend we did it everything went without a hitch.