How did you arrive at the 5 units of Caninsulin? Start at 1 unit and increase? I'm just wondering if 5 units was a safe dose of Caninsulin. If it was, then 5 units would be the starting dose of Lantus. Note, my Neko started out at 1 unit of Caninsulin, and increased up to 5 units, at which point I switched to Lantus. Unfortunately, we started at 1 unit of Lantus per the vet and it took me three months of slow increases to get back to 5 units of Lantus, which turned out still not to be enough insulin. Typically when someone switches from one other non depot insulins to Lantus, we take the existing dose into consideration and how kitty is doing on it. Did you have any blood sugar data from 5 units on Caninsulin?
Reading the spreadsheet, it sounds like he really needs a dental and is on antibiotics for now. If your vet can refer you to a dental vet specialist, they may be willing to do a dental on an unregulated cat. Actually, my regular vet was comfortable doing that too, but not all general practice vets are. Getting a dental can make a huge difference. In fact, cats with bad teeth often cannot get regulated, hence the difficulty in waiting until the cat is regulated before getting the dental done.