Cold idle struggle on 95 octane. Would "fast-idle" tweaking fix that?

[2nd Hand Yank]

After my car's been running for 2 minutes I have no complaints with idle.
Before it, it's terrible on 95 octane, even when I depress the throttle which supposedly engages the choke.

Is my choke working properly?
Should I check that first?

Or should I just increase my fast idle power?
Back when I used 91 octane, sometimes fast idle was quite fast, like another 500rpm,
so maybe my fast idle circuit isn't even working lately.

[FujiFan]

I use 95RON with no probs in my 92 wagon. The octane rating should make no difference to starting cold or hot IMO. No adjustments to the carb are necessary, but yes - is your autochoke working correctly!! Perhaps its having an episode:???:
For myself, Sh!# always coincidentally happens when I change something or do something different;)
Make sure everything (incl. ignition) is as is should be before "adjusting" anything.
Also the warmer seasons may come into play here.

J