That's okay! Do watch him though, it's entirely possible that 1u is how much he ends up needing, but you want to do it slowly and build up to it.
Here's some different info for you ... Novolin is a very harsh insulin and has more strict rules to it, so Prozinc's are a little different.
Prozinc
You can test, feed, shoot all within 15 minutes (or however long it takes you to do it all). Prozinc is a slow-acting insulin so we normally do not see insulin hit the system until 2 hours later. Therefore, as long as Diesel is showing an interest in food, it is considered safe to give insulin the same time he is snacking.
Do not shoot anything under 150. Between 150 and 200 you can skip, give a token dose (which is 10-25% of the regular dose - so if regular dose is 1 unit, a token dose might be 0.25 units), OR feed and test in two hours and decide a dose based on that. That will throw off your schedule however!
Any drop under 90 at ANY time earns a dose reduction of 0.25 units!
Instead of snacks every hour like with Novolin, a good general rule is to give snacks every two hours (or so). So a snack at +2, +4, and +6 will be a good start. Why do we do this? For one, cats in general do better with multiple small meals than just two big ones a day. It is easier on the pancreas and helps it to heal ... remember, with diabetes the pancreas is damaged, so we are essentially nursing it back to health! The other reason we feed snacks is to "steer the drop" of insulin. Onset (when insulin begins working) is normally around +2 with Prozinc, so we feed a little bit at +2 to keep the insulin from dropping too fast. The food slows it down. We also do it a couple more times before nadir (when insulin is working the most, and BG is at its lowest) to keep it from dropping too much/fast. We recommend the bulk of food be given prior to nadir, as food after it can "burn up" the remaining insulin faster than we'd like, and ultimately not last the full 12 hours. Right now, we do not know what Diesel's onset and nadir is yet, it varies cat to cat. Onset is usually +2, and nadir is usually between +5-7. We can change snack time accordingly.
Here is a loose guide for you to follow ... does not have to be exact, this is just a guide to help you fill in the "gaps" on your spreadsheet.
Snacks @ +2, +4, +6 (you CAN feed more than this!!)
Test @ +2, +4, +6 one day and +3, +5, +7 the next. Zigzag so you fill the gaps on your spreadsheet
Get at least a +2 at night and a "before bed" test to make sure he is safe.
BG: Blood glucose, or blood sugar
Onset: When insulin kicks in and BG starts dropping (usually +2)
Nadir: When insulin is at it's max effectiveness and BG is the lowest of the cycle (usually +5-7)
Cycle: A cycle is 12 hours. There are two cycles per day (24 hours). A cycle begins when you give a shot and continues until the next shot 12 hours later.
For your spreadsheet understanding:
AMPS: AM Pre-shot. The test right before the morning shot.
U: Units given. It's best if you keep it simple. If it's a half unit, we put "0.5", or if it's 1 unit we put "1".
+1, +2, etc: This is how many hours have passed since the last shot. +1 means one hour has passed. +2 means two hours have passed, etc.
PMPS: PM Pre-shot.