I've done a few times, and found that a heroic throw when it spawns and shockwaves (you shouldn't get hit if you stand at absolute max range) was enough treath to keep aggro from a holy pala with righteous fury active and vig on that paladin.
Although, I did have severe issues when we happend to get 2 big ones in the middle of the fight. Doing a shield slam before it gets "active" and saving the heroic throw incase you should get a double spawn at some point seems to be a viable way to go. And this is on heroic, I've never tried on normal.
Intervene through slimes = win
On LK I don't use the taunt glyph because I want to maximize my survivability, and I certainly don't have 17% hit since you need to be spell hit capped to make taunt never hit capped. Using vig on the MT when tanking ghouls didn't pose any problems for me, and even less on hc since the dps is moving a bit. I've made a macro to apply and remove vig from the tank, and I always apply it right before the soul reaper hits incase my taunt miss, as well as right before I soak vile spirits in the last phase. Tried this with both a pala and druid tank, and they had more than enough threat for me to safely use safeguard if it's needed
I'm having a tiny threat issue myself though, when I'm MTing in P1 with the spec I'm using. If you're using 2 warrios, and both using a survivability focused spec, this might pose a threat problem. Or just MTing as a warrior in P1, and then having the other tank MT in the last phase while you're using safeguard. This is what my guild usualy plans to do, but I never intervene anyways as the palas AD never procs, and we're using safeguard as a "oh shit" if AD should proc.