The swirly in those I like, the jittery part not so much. If you want the jittery, go with the older Zeiss, if you just want swirly, then it gets tougher, but you should definitely try a 50/1.2. Here are a couple shots back when I had mine. Note I sold this lens because I preferred the overall rendering of the 50/1.4G, but YMMV.
50/.2 wide open, albeit on a D810 so for bokeh rendering -- the first you can see the swirling in the foreground bokeh, which is rarer than background swirl:
At 1.2, the background blurs pretty quickly, so the swirl is equally shallow:
Again, overall I prefer the look and convenience of the 50/1.4G, and sold the manual-focus 1.2. Oh, the absolute resolution of the 50/1.2 is behind the 1.4G, which is a notch again behind the Sigma ART -- but the ART had fairly so-so bokeh; nervously smooth rear, but little swirling and not much going on with a little more nervousness in the foreground:
50 ART wide open (older image on D800, again for bokeh):
But laser sharp --at least on the D800-- even wide open:
If I regret selling any lens, it's the Sigma Art 50 as it was an incredible landscape 50. But it's also a tank relative to the 1.4G and resolution is "close enough" for my needs, so the G won out. Upside is I can acquire another Art pretty easily whenever the mood strikes
Hope these help!