You're a brave man....
The Westphalian gunners wore blue/blue uniforms, very much like their French mentors. In fact, the artillery uniforms were almost identical to the French foot and horse, respectively, except that the Westphalians had solid red collars, instead of blue piped red.
BTW - I have a long article on gaming with the Westphalians - not the same article as the one on the "History" page of this site - that's appearing in the January issue of Wargames Illustrated. There will be some scenarios and army list info there, as well as some painting guides.
In the words of Monty Python's Michael Palin... "...not dead... lovely plumage..."