For what it’s worth, I had Jim C rebuild my SD40 carb and he could not get it to run perfect on his “test rig” without a little choke. I think he uses a 2f on his 60 series with a manifold adapter to run the older carbs. He knows how well his rig runs so the only variable is the carb. He...
Make sure to note the orientation of the adjusters with the ramped slots from the existing cylinders and install them the same way on the new cylinders. I haven't seen new cylinders with ramped slots but City Racer seems to get the details correct so it might not be an issue.