I am the developer that took over maintaining these features after the summer student Rohan implemented them and put them into 2.8.
I agree that the UI for doing things is very tedious. As Alberto said, the UI was a little better when it was in 2,79 with a tool shelf section. But I’d really like to make some custom gizmo to edit these normals. Just didn’t have time yet.
I found that some of the shiny matcaps (especially the one that reflects a circle with a line through it) did a reasonable job of showing the effect of editing the normals on shading, Also you can turn on the vertex per-face normal display in Overlay (in Edit mode). Though that only works if you have already applied the Weighted Normal modifier, which I know isn’t a great solution for normal workflow.