Is it possible to revise a tummy tuck in stages?

The more times you revise the area the more chances for complications or contour issues. I encourage you to visit with a board certified plastic surgeon to discuss if you'd be able to remove enough tissue with just one revision.

Advancing skin, even 'slowly', would require re-elevating the entire skin-fat flap of tissue off of the abdominal wall to make any headway; essentially a revision tummy tuck every time. The good news is that your concept is not necessary. Chances are (you provide no photos) an expert body contouring surgeon can give you an excellent result with a single surgery.

For question like this it is best to contact an experienced board certified plastic surgeon in your area. Scar revision after TT is possible but only in person evaluation can give you appropriate information. Good luck.