The size is adjustable in - Budgie Desktop Settings / Top Panel / Settings / Size
Divided, well they use a black line change to transparent and you will see, as long as wallpaper is not black 😀
The +2, +3 means you have 2 , 3 windows open in that Workspace. Left click will drop down a panel to select a window.
Right clicking an open app icon - the arrow will open a workspace control window.
I have my Workspace panel centered to give it room and use 4 panels daily or more
Once you get use to it, I find it very natural. 🙂