You are asking questions that I don’t have answers for. I will give you some suggestions.
Question 1. It could be a printing error but I don’t know.
Question 2. Looks like an engineering choice. The designers of the particular machines would have to answer that.
Questions 3 and 4. There is some information available by searching on Google and Wikipedia. You may find that some of the information is behind pay walls. Some university and public libraries have subscriptions to these publications.
The e-mail addresses for Saw and Lee are listed at the top of their paper. You can try sending these questions to them to see what they say.
