Tom,
You've been extremely helpful. Can you go into what you mean by "requests get made?"
I think if you Google something like "How the CBOE comes to set strikes" or similar, you'll get a whole lot more up-to-date than my little brain, but the CBOE will create an eligible strike-to-trade upon request of any "qualified" party, with a note from Mom. And so you'll see gaps in weird places, simply because nobody requested a strike. But if you're trying to provide a program framework for "all possible strikes" -- you will become *intimately* familiar with the fill-ins over time. UGH.