I would still watch for fluid incompatibility between the DOT 5 MC and DOT 4 fluid. A lot of seals will tolerate silicone based fluid, but be quickly consumed when exposed to DOT 3/4 fluid.
Jake
I will keep an eye out on the seals in the MC. That was my main concern, as I never intended to run anything but DOT 4 in it. The rubber being different was my biggest fear all along, but never anything I could confirm.