Alrighty. So yes, I'm outside of the US, and I will post US figures now, seeing as how I see the majority of you are from the States.

I know I need the urine test strips, but my cat only just got diagnosed with diabetes and the vet bill and purchase of the insulin ate every last ounce of my money for the time being, so i haven't gone to get them yet. I figured smelling for ketones was the next best thing, as that was what the vet suggested. I will work on filling out the spreadsheet as soon as possible.
In the meantime, her blood glucose has dropped back down to 342, which is on par with what I've been seeing over the last 5 days, which is precisely how long I have been giving her 1 unit (that's mmol, sorry I'll get your lingo figured out soon, I promise) of insulin twice a day at 12 hour intervals. I took the food away from my little piglet because her blood glucose was up so high and I didn't want to chance that she would eat and cause her blood glucose to spike even further until I figured out what was going on. Please don't think that I "took her food away" for any great length of time, or that I'm silly enough to starve my cat, lol. That is not the case. She's been nibbling again since. I only picked it up off the floor for about an hour while I figured out what was going on and until she started to come back down after the insulin.
I am still new at this, so if I sound ignorant, I probably am, just without the negative connotation on the word - I just don't know it all yet, and am also having to pull up my socks when it comes to this whole online/computer thing, I rather detest them and the internet, lol, and have avoided them/it as best I can most of my life, not entirely, of course, but it'll take me a minute or so to familiarise myself with the way these forums work and get the spreadsheet going.
I have two cats, the other a non-diabetic, and have been leaving food out so they can both eat at their leisure. When Artemis' BG was 585 this morning prior to getting her insulin, I believe she must have just eaten and really pigged out before we woke up for the morning, tested her, and gave her her insulin. I'm thinking it would probably be wise to remove the cats' food at night so this doesn't happen again? What do you think? The vet did tell me to make sure she ate AFTER the insulin, this makes sense... but I'm also really attached to the idea of letting my cats graze... Is their a general consensus out there on that? Not so sure what to do here... As for what kind of food, my cousin brought the lowest-carb dry food she was able to find and that's what she's been feeding her diabetic cat who is now in remission, can't remember what brand, atm...
I 'll get some more info together, like the particular brand of cat foods, and translate it all to/familiarise myself with - US terms, fill out the spreadsheet and get back to you all.
Thank you all for everything thus far, especially your patience

Danielle