I like the iso belt squat. I was doing those and really externally rotating hard and spreading the floor and it got me good. You can march with it, too. That annihilates the hips.
You can always use chains with the SSb to keep your CNS primed for when you go back to straight bar. As we know, the bar is a mofo and you won't be able to use as much weight. But it's a real mofo and is fun in a sick way to load it up with ~25% chain weight. Duffin used the SSB and 2-300lbs of chains to prep for his 859, citing the reasons I mentioned above.