Not a huge difference honestly. If you're mashing for a full hour in a mid-range temperature (152-153), you're actually going to get a very fermentable wort (I'll see if I can find the data on this) because both enzymes are fairly active in there and 60m is actually a very long time to mash. It helps to understand at a basic level what each enzyme is doing physically to starch molecules and why they work together in that way.
With well-modified malts, single-infusion is really the way to go. A decoction will give you some nice melanoidin formation and caramelization, but the actual step mash part of that isn't particularly important, in my opinion. Many, many people will disagree, though. Old traditions die hard.
I can't be arsed to keep up this list of what's in the fermenters, but hey, check out the cool brewery I own!
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