Re VSL, try some of the techniques and see if they are helpful -- you have nothing to lose.
If it works, beats spending a fortune on counseling and neuropsych testing, and possibly encountering folks quick to prescribe a drug.
What would be really interesting is to see some double-blind studies showing the effectiveness of different therapies of say dysgraphia and ADD for kids who are gifted and HG+.
As to general discussions of visual-spatial learning and the merits of it; that would seem more appropriate in its own thread.