I believe the "Managing" class here would refer to higher level people who dictate down and make enough to be comfortable, but nevertheless is closer to the ruling class than the average person, without having much influence inside the ruling class.

Your average manager covering a small team of people (e.g. say a fast food manager or a retail manager) is still working class, they just happen to be one step higher in the hierarchy , with slightly more pay but relatively little power.

At least that's how I have always viewed it. My definition could be completely wrong though.

I think the ruling class has done a skillful job of convincing the managing class and the top of the working class that they are almost at ruling class levels themselves.

Yep, they have done an exceptional job at that ever since the more subtle forms of union busting occurred during the 70's and 80's. I am getting a sense that idea is starting to change though, thankfully.

People whose income is generated from the management of their estate or finances. A gentleman.

The way I learned, gentlemen could support themselves from the fruits of their investments alone and did not need to labor to afford their expenses.

You didn't need to have great wealth to be a gentleman, but you couldn't afford to rise in your station without it.