It has never been clear to me how to book a specific fare class on United like it is on several other airlines. I usually never care, the cheapest will pop up and I go with it. But when wanting to book an upgrade-able fare, I can select the upgrade I want to use at the flight search screen and I should then see the right results.

Except I do not. The only clue I have when looking at the search results is the little icon and phrase "upgrades may be available" which of course they also tell you does not mean they are available.

I have learned I have to click on each flight option, click "continue" to see the fare class. or I can select "Fare Rules" and then select "Rule Details" and there is a subtle positioning of the fare code in the top bold line of the fare details. This all way too much work. And it will be a bit more important when the Y/B fare upgrade priority rule kicks in. If I was purchasing a fare that was just a small amount of dollars below the Y fare, I would be crazy not to take the slightly higher fare and get the instant upgrade. United has long been much more a "hide the fare structure" airline, unlike, say Alaska or Southwest which lay out all the fare options and prices in front of you to choose from.

As a test I searched for a one way economy fare from SMF to ORD. I did one search specifying use of a Y/B upgrade and one search using no upgrade. Several things became apparent
The B fare is $809
The E fare is $228
The W fare is $252
There was no way to pick a B or Y fare except on the direct flights as the non direct flights stayed at the discounted levels and did not show upgrade eligibility.

Is it too much to ask to search and get a chart of flight/fare options to choose from? It will certainly be more relevant when Y/B fares get instant upgrades. Here I would not really want to buy the B fare since it is 4x the available fare and $600 more.