KDE Desktop on a UHD 4K monitor

[Jerome Yuzyk]

My new desktop machine has been my introduction to 4K screen resolution. 
Fortunately my eyes can handle most everything being smaller, so now I have 
gobs of pixel real estate and after a settling-in period with my old 
1920x1200-based layout I'm wondering how I can use it better.

My KDE __?__ Bar has always been 100+ pixels vertical along the left edge of 
the screen and it'll stay that way. I like my app windows to be as tall as 
they can.

The largest waste of space though is the Task Manager because it's very 
unlikely it'll be filled.

I use 3 virtual desktops with some windows on All desktops. I'd like to 
separate them, with a spacer or something, from the desktop-specific windows. 
Is anyone doing that? Or is there a way to have two Task Managers and put some 
stuff in one and let the other one catch the rest?

Now for that extra space. I could either put applets on the __?__ Bar, or make 
it shorter and put a window.

How do you folks use 4K of pixels for your KDE Desktop?