Actually, I think it's the SG that does all the swirl filling, not AIO which can't layer. That's where the recommendations for multiple SG coats came from. I honestly can't remember how the finish looked after AIO alone, but I know after a few SG coats, light/fine swirls were filled (though I only found this out later). Any deeper swirls were still left though.
I know we've talked about this before Simon, but I still stand by the suggestion that Klasse SG not be applied over a glaze. The usual reasons you get for this is bonding, but besides that, I'm (now) wondering what happens when you put durable SG over the short-lived IHG.... For this reason alone I'd like to keep my system "pure" and just polish out swirls, then layer on the SG to get what the polishing missed.
For "moderate" swirls you can always try Meguiar's DACP, which a few people have successfully used by hand. I've heard FI II needs lots of working in, so I'd leave that for machine use.