It's not relevant for a toddler, but for future reference, another thing to look into is inhaled insulin (brand name in the US is Afrezza, not sure if it's available elsewhere or under what names). The big benefit is that its onset is very fast and duration very short, so you don't have the inject + wait 20-40 minutes cycle. And if you accidentally take too much, you're not dealing with hours of lows because the duration is short. Most people I know who use it wait until after they've eaten (or maybe in the middle of he meal if it's big/long), based on readings from their CGM. It's not perfect, but it's a good tool to have in the toolbox.