First of all, I searched. The search engine threw out "e+" which everyone uses because it was too short and economy plus yeilded few informative results.

I have an upcoming trip to GEG (spokane, WA) and I would normally just book onto NW, but UL flight times are better.

I fished around United's website but could not book into "economy plus" but I see the cabin on seat maps. Can you book an economy plus seat via their 800 #?

I like NW becuase at online check-in I can usually snag exit rows or a an empty seat in their elite section, can I place myself into E+ at check-in? Can I move into an E+ seat once the door has closed?

It seems odd to put in a Y+ class but not be able to book into it.