I just tried out Scarf Heatran + Scarf Abomasnow briefly in Multi, and it's working nicely so far. It's early days, but the extra speed on Heatran definitely helps me because I can take on more stuff without being forced out. The problem? It takes ages! I did 14 battles and it took at least an hour and a half. I had to battle some stally pokemon like Umbreon, and all of those turns of hail damage really slows things down!