Howdy 64Falcon:
I always start with what was in the stock carb and tune from there. There are so many variables. For example I live at about 5,000 ft elevation so I almost always have to find a smaller jet for my applications. Another factor is the size and original application for the Autolite 2100 you are using. The 1.14 and the 1.08 carbs are very similar in CFM flow, but were typically used in different applications from the size of FoMoCO vehicle to the year, mileage and emissions concerns. All Autolites were leaned in various ways after the 1st oil embargo of the seventies.
Typically, I never change more than 4 numbers up or down. And FYI, the main jet will have it's most significant influency on WOT. It will have an influence on steady state cruising, and none at all on idle quality and transitions.
So, the questions are; what size Autolite 2100 are you using and in what application? What is the stock jetting? Do you know wnat the 2100 came from? Is the tag still on it? What is it acting like? What do your spark plugs look like? Is the 2100 direct mounted or with an adapter? Any other modifications to the engine?
Autolite jets are scarce. I have gleaned jets from junk carbs for years. They clean up easily and nicely sitting in a cup of vinegar overnite. I hear that Pony Carb is a source for Autolite jets, but I have not tried them yet.
Adios, David