Well, Cinnamon's history does make this more complicated for you. But not impossible - we have people here who have gotten blood glucose readings from very skittish, fearful cats. It may take a little longer and some experimenting with things, but it is possible.
One of the first things we can offer is some hands-on help. You're in Brooklyn. We certainly have members in New York, so I will post over on Community to see if anyone can help. And if no one sees it here, post again with another subject like "Hometesting help needed in Brooklyn". It is amazing how much help it is just to have someone talk you through it, even if they can't touch Cinnamon.
Another idea is to use the clothespin trick. Several people with difficult cats used this at first. After a while, they were able to get readings without it:
http://www.felinecrf.org/giving_sub-qs_ ... _peg_trick It doesn't hurt; it mimics the way mother cats hold their kittens by the scruff of the neck.
To eat him eating, see if some of these ideas will help:
http://www.felinecrf.org/persuading_cat_to_eat.htm The fish mixture will be okay for a while; it isn't all fish so the mercury issue is "diluted" a little. You do want him to be interested in several flavors, so keep trying. You can buy single cans and try them out. Any unopened cans he won't eat can go right back to the store; they are very good about taking it back.
Another thing to start is the rice sack. Fill a thinnish sock with raw rice, put it in the microwave and heat until very warm but not hot. See if Cinnamon likes the sack on his body, and hopefully eventually on his ear. Just warm him up - no poking yet.
I hear through your words that you might be frightened that doing this will hurt your hard won relationship with Cinnamon. We understand; lots of us worried about that. But please believe us, what we have experienced is that as a group after you get a routine down, and you and your cat are working together, you become closer. It is true that eventually cats go to the testing spot and some purr through the testing. It may take time, but we want to help. You need to make this work. We won't give up; please don't on your side either.