Here's a new toy to play with: pre-pre-bolusing.
My work hours are fairly flexible, I'll have 2 or 3u to pin anticipated foot-on-floor when getting up before getting to work about 9:30, then I slope off for lunch at about noon with a 20 min or so pre-bolus.
So I've got the pre-bolus starting to get to work, but I've also got the earlier 2 to 3u, which has dealt with the fof, and is past peak but still well active.
Was messing about with basal levels over the last few months, turned out 14u was far too low, so I'd be firing in 2u or so late afternoon to stop a rise about an hour or two before leaving for home and tea, which again involved a 20 min pre-bolus.
So, again, I've got the pre-bolus but also the 2u deep into its activity.
In these sort of situations, I'm really not seeing spikes at all.
Switch to Dana Lewis's book, Automated Insulin Delivery. She describes how the Eating Soon algo works. In a non-T1, glucose is absorbed by the small intestine, then goes through the liver before getting into the bloodstream, and most natural insulin goes straight to the liver as an instruction to store the glucose in the liver before it gets anywhere near blood, which is why muggles don't really get massive spikes, because their insulin goes to the liver whereas our injected insulin rarely does (although whether the HDV gig will change that remains to be seen).
Dana's theory is that if we pre-bolus an amount sufficiently far in advance of a meal, not just your usual 20 mins, but an hour or more, a small amount like 1 or 2u, not enough to send you into a rapid drop, then by the time you come to eat, it'll be heavily into it's active phase and some of it may have actually reached the liver, where the heavy spike buffering happens, so a much higher chance of not spiking.
I hesitate to disagree with Dana on the idea of it getting to the liver as she is very clued up, but agree absolutely on the idea of the importance of the stage of activity.
It does seem to work, the idea of layering or stacking insulin, a small amount quite far in advance of a meal, not enough to rapidly drop but hitting peak activity, along with a 20 min pre-bolus just starting activity.
As ever, YDMV, but I'm finding it really effective.
PS: the hdv gig is "hepatic directed vesicles", a few companies are playing with a compound which gets added to ordinary insulin and by some biological magic, it "taxis" the insulin straight to the liver instead of just randomly wandering around the body. The thinking is that cos 80% of natural insulin goes to the liver, so should injected insulin.