My son is also T1 and we go thru the same things you are. We've been at it since July with Blake, so here's what I see in his trends so far. Blake is 2.
1. Testing an hour or two after a meal and seeing a spike: This happens to Blake as well. I write every single thing down on a tracking sheet that happens throughout the day to see what is affecting him and how things affect him. Different foods act differently in eat person. For example, strawberries will spike his sugar but then come back down within 30 minutes. Crackers will spike his sugar and keep it elevated for an hour and a half or more.
****Track his foods and levels of activity. I write down what he did (did he sit and watch tv all day or did he run 15 miles? Those will be factors
2. What do you do about a high after a meal? Nothing, except make sure he's hydrated. You can't correct for sugars <3 hours if using Novolog/Hum. anyway. Just be patient and see what's happening b/w meals and boluses.
3. How long does insulin stay in the body? Open your box of insulin and read how it acts. The paperwork that came with your insulin (find it on line too) will give you a graph that shows how it works in the body. We use Novolog, so I know that around 2.5 hours after I give the bolus, it's working its hardest. That's when I'm most concerned with checking sugars and giving a carb snack. Blake's target is 150, so if it's higher than 150, I wait for about 30 minutes then check again.
****You're dealing with a child, who may or may not communicate with you properly, so if you are concerned about the sugars, check them! "Check, don't guess". Don't worry about what other people are doing. You know your kid better than your Endo.
4. Your 275 question about doing something or doing nothing: You shouldn't correct for BS >3 hours b/c your Novolog/Hum won't be working it's hardest until 2.5 hours. What you CAN do is track what's going on and how foods affect him.
****Some things to think about that increase BS: illness (ear infections, URIs, etc), stress, anxiety (meltdowns), different types of foods (milk, juice, grapes, any food in the high glycemic index) will raise sugars to undesirable levels. I still give them b/c I'm not going to neglect nutrition in terms of fruits or fiber foods for a fear of having high sugars.
5. Readings with a minute: Yep, that's actually what's going on in his body. Children, especially those who are younger than puberty, are going to be fluxtuating dramatically. From what I've researched, there is no clear link for children younger than puberty to have long term complications related to continuous highs. However, we should try to reign it in. The reason is that in their time before puberty their going to grow about 5 new pancreases and kidneys b/c they're growing.
Keith, all you can do is do your best. As long as he's eating nutritious meals, low saturated fat and exercising, it's going to be ok. There was a time when I freaked out for a few days. All you can do is do your best. It's going to be ok! I promise. People who take care of themselves live to their 90's with diabetes and your son won't be any different if you're trying to figure his body out and work on the best ways to reign the sugars in.
Hope this helps.