Ovale can do this, but you're basically doing a very simple priority list.
If Mangle is up, Mangle
If FFF is up, FFF
If Lacerate has less than 6 seconds left or less than 5 stacks, Lacerate
What I do is just two different spamming patterns when i'm tanking single targets. First spam (in order) Mangle, FFF, Lacerate until you have 5 stacks of lacerate, then switch to spamming Mangle, FFF, Swipe until the lacerate stacks have 6 seconds left, and repeat. It's basically two button tanking if you have those two macroed, and Mangle and FFF will be used every cooldown. This will give you plenty of time to concentrate on the other boss mechanics. (Keep demo roar up too.)