If you have threat problems after a swap, try holding on to Exploding Keg for it, and use it in the taunt window. Pindrop has already alluded to it, but it makes a hell of a difference, so I'm going to emphasize again. Getting your taunt multiplier on EK is a ton of threat.
For the timings mentioned above: It can help to activate RJW twice during the pull timer, for example at 7 and 1 if your CD is < 6 sec, because you get some of the duration left added, so you don't need to recast it during the early part of the fight and the timing for EK is a bit fluid, because it depends on your distance from the boss; on Fallen Avatar I can throw it at 2 and not prepull, just due to where I'm standing.