Generally speaking, (and keeping in mind that every cat is different (ECID)), the longer a cat is on insulin and the more regulated they become (consistently remaining in lower numbers), the shorter the bounces are and the less extreme they are. Bounces are a "natural reaction to what the cat's system perceives as a BG value that is "too low." "Too low" is relative. If a cat is used to BGs in the 200's, 300's, or higher for a long time, then even a BG that drops to 150 can trigger a "bounce." Bouncing can also be triggered if the blood glucose drops too low and/or too fast. The pancreas, then the liver, release glucogon, glycogen, and counter-regulatory hormones. The end result is a dumping of "sugar" into the bloodstream to save the cat from going hypoglycemic from a perceived low. The action is often referred to as "liver panic" or "panicky liver." Usually, a bounce will clear kitty's system within 3 days (6 cycles)."
Following the dosing method guidelines and taking increases (and decreases) when indicated can help get Reg's numbers down lower. As you're beginning Reg's treatment, feel free to check here on the board regarding dose increases/decreases. If you hold doses too long--meaning when he is remaining in higher numbers beyond the dosing method's indications for dose increase--you run the risk of glucose toxicity, which makes it harder to get them down from those higher numbers. When cats remain consistently in lower numbers, they can experience healing of their pancreas, which can lead to remission. So getting him down into lower numbers will increase the chance of remission. Not every cat experiences remission, but it's a good goal early on in treatment as that is the time when the likelihood of remission is greatest (though I've seen long term diabetics go into remission).
Most everyone here understands the concerns--the fears--of lower blood glucose numbers. Right now, you are building data with those tests that are showing you how his body is responding to the insulin. That data will be of great help as you increase his insulin and his numbers go lower. For example, yesterday morning and last night, his numbers were relatively flat. He bounced last night, but look at how flat he remained. This is really fortunate for you! A lot of kitties are up and down and all over the place. Not Regs! Steady Freddy! Now, he has had some extreme spikes, like on 8/17, but generally speaking, he's fairly flat. So, I say this data helps because, as his numbers drop, you might expect the same flat cycles, only lower (maybe--cats always like to keep us on our toes!!).