What yeast in Dark Strong

I am about to make my third belgian dark strong ale. The first one I made with Chimay yeast and aged for six months it was one of the best beers I made. The second one is only one month old in the bottle it was made with Westmalle yeast. I have some Chimay washed yeast that is 4 weeks old and a new vial of Achouffe yeast. I also have some Westmalle washed yeast that is 3 months old and smells bad I dont know if i should use it. Has anyone made a Dark Strong from the Achouffe yeast?

I haven't, but I definitely would. Go for it!