He's on a mission!
This next part is up to you. Hes technically in normal numbers for a non diabetic cat, but I do think he could use some insulin support a little longer for a strong remission. But it depends on your comfort level and ability to monitor.
Typically next we'd go down to 0.1U. But I'd you're uncomfortable with that, you can also try a drop dose. That is where you push the plunger down as hard as you can, insert into vial, release the pressure. Result is single drop of insulin in the needle itsf, not visible in syringe. When giving the shot, do your best to hold that plunger down again for about 10 seconds to give the insulin time to absorb.
You could also try an OTJ trial of you're not comfortable, but in my opinion that's a little premature. I'd like to see more greens and lower preshots.