My daughter was 3 when diagnosed and we experienced a similar situation.....Once the high blood sugars had been treated for a couple of weeks her requirements dropped considerably. For a period of months she only needed small levels of background insulin and no Nova Rapid...for us, carb counting was a pointless exercise at this stage, her body responded very differently from one day to the next and even half a unit of Nova Rapid would typically send her hypo. We therefore moved to the pump 9 months after diagnosis (we've found the granularity of insulin delivery to be invaluable).
In my experience, the ‘honeymoon’ period is a bit of an enigma, our daughter, 4 years since diagnosis, still has days when her insulin requirements drop considerably and even very small amounts of insulin send her hypo....and days when her requirements are comparatively high.
Until quite recently her insulin to carb ratios for lunch and dinner were to 1 unit for every 35 to 40g of carb. Over the past few months we have seen that increase quite substantially for the first time....she now requires c. 1 unit to 22g.
For our daughter, the exception is breakfast....the typical high carb breakfast with items like toast and cereal are a disaster for our daughter....doesn’t matter what I’ve tried to do with manipulating the insulin she will spike into the teens and then crash. We therefore keep carbs to a minimum at breakfast (she will typically have eggs with tomatoes or similar). I also never give her pure carb meals (at any time of day with the exception of low GI items like apple etc.).....I find combining carbs with protein, fibre and fat makes a huge difference to stability. For example, I never give her a plain piece of toast, however, a piece of toast with cheese melted on top and some tomatoes on the side will have minimal impact on the rise and fall of blood sugar (she has CGMS so we can see very clearly the impact different foods have on her body.....not just where she is from the finger prick 2 hours post meal.... it’s been an invaluable tool in the steep learning curve of trying to master how to replicate a working pancreas).
Personally, I totally agree with your decision to reduce insulin. My diabetes team did in the early days try and insist that low levels were due to insufficient carbs. They gave my very petite 3 year old (she weighed 11 kg) a target of 160g of carb a day....with the goal of trying to get her to tolerate 0.5 units of Nova Rapid....with the benefit of experience I kick myself for initially taking this advice at face value....a pump was what she needed to deal with her very low insulin requirements, not a diet full of starchy carbs!
I note you mention using Glucogel to treat lows...I’ve never had the need to use Glucogel (my understanding is that it is for emergency situations when you couldn’t get other fast acting carbs consumed.....I’ve been told it’s rather unpleasant too).....have you tried using juice or similar? This may be an effective alternative which is more pleasant for your little one.
If I can be of any help, please feel free to drop me a line at any time with any questions. Best wishes and good luck.