Most likely the 26.6 (478) is a food spike.
Fancy Feast pates and Friskies pates. Some people generate towards the Weruva. It's more expensive. It all boils down to whatever the cat will eat.
Lantus. Available at any pharmacy. Humans requiring insulin need a prescription. Cats do not. Just say it is for your cat. (My vet marked up Lantus. It was my pharmacist that put me right.)
Strips. While Lantus is cheap in Canada, strips are not. AlphaTrak strips are crazy expensive. Human meter strips are less, but still expensive. The FreeStyle Lite is a human meter that many people use. Strips run about $0.80. You will go through more strips than you think. A lot more. For human strips, wait for Seniors' Day at Shoppers Drug Mart. Get a senior to go in and use your PCOptimum card points to pare down the cost.
Housekeeping. Can you add what time zone you are in to your signature? We have members here from all over the world and it helps to be able to judge the right time, especially at night. Also, when you do the food change, you will have to change your signature. Also, if you have been feeding the dry, and drop the carbs suddenly, you will see a drop in numbers of up to 100. It is best to cut out the dry food on a day when you will be home to get some tests in, especially mid-cycle tests. Lantus is based on the nadir (the lowest number) of the cycle and not on the preshot numbers.
2.5 units is a big dose for only 6 weeks in. Can you give a bit of history on that? It is generally recommended to increase in 0.25 unit increments so that you do not go right past the correct dose. I'll let other, more experienced with dosing people weigh in on this.
Looking forward to seeing your spreadsheet. If you need any help, just ask. There are a few spreadsheet gurus here who can set it up for you in minutes.