A little late to the discussion, but:

There were at least two dragoon regiments named Vasse-Dragoons after it's owner at different times.

a) Regiment Peysonnel (1674). became Gaubert in 1690, d'Albert in 1700, d'Amiens in 1701, du Heron in 1702, Bournoeuf in 1705 and Vasse in 1706. Uniform in Letrun p.32

and

b) Regiment Gevaudan (1689), became Vasse 1702 and Pourrieres 1705. That's the regiment that was at Blenheim. Uniform unknown, picture of the Guidon in Letrun's book p.58

Information about the regiments owners from C.A. Sapherson, The French Cavalry 1688-1715. PDF available in the web.

So at least with this regiment you might feel free to paint them as you like. I have in fact painted my Mestre de Camp-General in their old yellow uniforms - though probably historically not correct - but there's a famous picture by John Wootton of the Battle of Blenheim, showing Frech dragoons in yellow uniforms fighting allied infantry, if you take that as a reference it might justify the choice.