Jeff,
I apologize for not getting back to you sooner. I know a fair amount about those engines and would be willing to help you. The most important thing is, those carbs are super fragile, so use care when working on them. The castings were not strong and often they decay. Fortunately, a Speedifour carb will work on that engine, but the bigger Speeditwin doesn’t have many options other than the original carb due to size.
I’m listed in the directory if you’d like to chat.
George