I second the idea that VT is tedious and not easy. My son participated in 6 months of weekly therapy and during that time, 20-30 minutes of home exercises each evening. His tracking improved slightly after therapy, but his visual motor skills did not improve appreciably. He continued OT during the therapy - handwriting never improved and we gave up after third grade.
When he was tested in 7th grade, his tracking and visual motor had regressed. Although the neuropsychologist suggested resuming the therapy, we chose not to.
I have heard that VT helps some people, but we found the improvement minimal and not sustainable.