The only real thing that wears out on an Amal carb is the throttle slide and bore, and the needle and needle jet. If the slide still seems to be a fairly snug fit then the carb may be ok. However, it might be worth replacing the needle and needle jet because it's difficult to know when they are worn out but, after 50 years, they might be. The slight differences in carb settings listed in your table including the choke sizes won't make a huge difference to the way the bike runs or starts although it's best to start with the needle position near the middle. The same is true as to whether you have an air filter fitted or not. In general, the standard B40 is a mild mannered beast and should start reasonably easily after tickling the carb. If the carb turns out to be ok then poor starting might be down to another issue with the engine (ignition timing, compression, etc).