Thanks for your responses!

To answer the questions:
--No, not mileage upgrades. I'm looking for either instant (since I'm on a Y-class ticket) or 24 hours ahead of time. My understanding was the full-fare economy upgrades (like Y-class) fell under the PN bucket (at least that's what http://milecards.com/1588423522/how-...s-illustrated/ and https://thepointsguy.com/2016/01/usi...d-expert-mode/ both say)
--Domestic
--Mostly on direct flights, so I think there's only one place to look?