Hi and welcome Sarah and Titus. I'm sorry about the diagnosis and it's perfectly normal to feel overwhelmed right now. But, and I am serious about this - having traveled this path along with most of the other members here, that lessens over time as you learn the "sugar dance".
You have created the signature, thank you very much. When you get that glucometer, please add that to the signature so we know that you are using a human meter. The space allowed for the signature is limited and we do abbreviate to get it all in if we need to and have room for the link to the spreadsheet.
Next, please set up the spreadsheet so you can begin recording the insulin dose and it will be ready for testing data when you begin that:
FDMB Spreadsheet Instructions
Understanding the Spreadsheet/Grid
If you need help with the spreadsheet set up, let us know. There are members who assist or can set it up for you.
We recommend feeding frequent, small meals to our sugar cats. It helps even out the blood sugar, reduces gastric issues from not eating for long periods of time (twice a day feeding) and supports kitty as unregulated cats can't utilize food properly and they are usually extremely hungry. Many members feed 3-4 meals a day, plus snacks. A timed feeder is a very good way to accomplish this. PetSafe and CatMate are two brands that I know of that have both 2 and 5 dish feeders that you set to open at certain times.
Idjit was about 18 # when diagnosed I was instructed to feed about 300 calories a day, plus he got snacks. When I bought the canned Fancy Feast and Friskies foods, I used a marking pen and consulted the
FOOD CHART and marked the total calories and carb % on the side of the can on the label. That way I knew what was going in on a daily basis. I don't think you have to be extremely precise, just ball park this and see how he feels. I do suggest that you gradually transition any diet change, especially from the dry food to wet as introducing a low carb diet can significantly lower blood sugar but
you need to be testing before you make changes to prevent any critical low blood sugar events:
Transitioning your cat from dry to wet food . So, please don't make diet changes until you are testing.
Divide the 300+ calories into 3 or 4 meals a day, and leave him a snack or two for night time.
You can visit
www.catinfo.org by Dr. Lisa Pierson DVM who compiled the food chart.
Dr Pierson recommends " start with protein minimum of 40, fat maximum of 50, carb max of 10, and for cats with kidney issues....phos less than 300."
Right now I would not worry about Titus losing weight, the main concerns are regulating the blood sugar and making sure his BG (blood glucose) does not drop too low. Testing is the best way to keep him safe and see how the insulin is working.
Here are some wise words by Chris & China (GA) about getting ready to test:
Here's something I wrote up for others for testing...maybe it'll help you too!
It can be really helpful to establish a routine with testing. Pick one spot that you want your "testing spot" to be (I like the kitchen counter because it's got good light and it's at a good height....it also already blocked 2 escape routes due to the wall and the backsplash) It can be anywhere though...a rug on the floor, a table, a particular spot on the couch...wherever is good for you.
Take him there as many times a day as you can and just give his ears a quick rub and then he gets a yummy (low carb) treat. Most cats aren't objecting so much with the poking..it's the fooling with their ears they don't like, but once they're desensitized to it and learn to associate a certain place with the treats, they usually start to come when they're called! Or even when they hear us opening the test kit!
You also have to remember...you're not poking him to hurt him...you're testing him to keep him safe and understand what's going on inside his body. There's just nothing better than truly understanding what's going on inside your kitty's body and with this disease, the more knowledge you have, the more power you have against it. The edges of the ears have very few pain receptors, so it really doesn't hurt them. Also, if you're nervous and tense, it's going to make your kitty nervous and tense too. As silly as it might seem, try singing! It forces you to use a different part of your brain!
It's also important to make sure his ear is warm. A small sock filled with a little rice and microwaved or a small pill bottle filled with warm water (check temp against your wrist like you would a baby bottle) works well
For new kitties, using a heavier gauge lancet is also really helpful. A 25-28 gauge lancet pokes a bigger "hole" than a 31-33 gauge lancet does, so look for "Alternate Site testing" lancets that are usually a lower number
Finding the right "treat" will be a great help too! Freeze dried chicken, bonito flakes, little pieces of baked chicken...whatever low carb treat you can find that he really enjoys will help him to associate the testing with the treat! China's Achilles heel was baked chicken, so I'd bake a piece, chop it into bite sized pieces, put some in the refrigerator and freeze the rest to use as needed. It didn't take long for her to come any time I picked up the meter!
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Regarding when to test, feed and shoot please visit the Lantus Insulin Support Group forum HERE and start reading. Lantus works best with injections 12 hours apart, always test before a shot to be sure the BG is high enough, and then shoot & feed, usually within about 15 to 20 minutes. I used to give Idjit his shot while he was eating his breakfast and dinner at 6 AM and 6 PM. Find shot times that work for you and Titus. It is recommended when you first start out on this journey to have the pre-shot tests be fasting..no food 2 hours before.
Test in between shots to see how low the insulin is taking the BG..Lantus is based on the nadirs, the lowest numbers in the cycles, not the pre-shot numbers. And testing at different times during the cycle on different days is going to show you where that nadir usually is. Be aware, this is a living body with all kinds of things affecting him, so there will be variations, nothing is ever going to plot out exactly the same.
Read that information in the Lantus forum, this information is going to help you help Titus. Ask questions about dosing, timing, or anything you don't understand about using Lantus in that forum. We also have testing videos and tips that you can look at here on the board.
I know this is long, and I apologize. But I hope this helps you get a little more grounded and feel less overwhelmed.
One last thing that would be good for you to read: How you can help us help you 
I’ll be at work at that 360 mark