On a 1080p monitor (1920x1080 resolution), my settings for the launcher panels are:
Panel 1:
  Mode: Horizontal
  Row size (pixels): 26
  Length (pixels) 1920
  --Situated at top (0 pixels from the top)

Panel 2:
  Mode: Vertical
  Row size: 28
  Length: 1054
  --Situated at left (0 pixels from the left, 26 pixels from the top)

Panel 3:
  Mode: Vertical
  Row size: 36
  Length: 1054
  --Situated at left (28 pixels from the left -- you have to manually adjust. 26 pixels from the top).
(In order to manually adjust the position of the panel, first uncheck Lock panel. That is an option made available by right-clicking. Further reading has more details.)

I have the applications selected that I want on the leftmost panel.
There is a separator between the bottommost launcher, which is Applications Menu. It has for it's settings, Style: Transparent, and [✓] Expand. The expand setting causes Applications Menu to be at the bottom of the screen.

On the panel next to it, which is 36 pixels wide in comparison to 28, I have an item called Windows Buttons. In the settings for that I have:
[✓] Group windows by application
That enables me to click on one of the larger windows buttons and select an application from a list if there are multiple applications of the same type open. I use Gvim for a text editor. If I am editing in two different instances, I can click the Gvim icon and select one to bring to the front.

You can also name Gvim instances. My gvimrc settings have these options, which enable you to type <F3> through <F5> when in ESC'd mode to name, save, and load a session. The session file will be named 's' in the directory where Gvim is open.

:map <F3> :call Name_Vim_File() <Return>
:map <F4> :mks! s <Return>
function! Name_Vim_File()
  call inputsave()
  let user_input = input('Name the window: ')
  call inputrestore()
  " Now you can use 'user_input' in your function
  " echo "You entered: " . user_input
  let &titlestring = user_input
endfunction
:map <F5> :so s <Return>

If you have named a Gvim window with <F3>, when it appears in the list as a result from clicking it's icon in the panel where applications are grouped, it's name will be displayed so it can more easily be distinguished. If you only have one file open, the name of the file is used.

Desktop Resolution
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I have in my plans, to use a 4:3 aspect ratio for one side of my new website. The other side will take up the remaining space. In order for a 4:3 aspect ratio to be used for an application, such as one of the games I'm playing (Old School Runescape or Luanti), and also have a window open in a browser next to it, which is what I oftentimes do, because the minimum size of the Firefox browser is 450 pixels, the size of the launcher panel on the left must be at most what it is currently set at - 64 pixels, which is the sum of the two panels' sizes. The size of the top launcher also plays a role in the size calculation.

I have adjusted the top launcher to have the date and time, like in Ubuntu (without Xfce). I used spacing separators in the panel to center it. I used two instances of the item called Clock, within the panel - one for Date Only, and one for Time Only.

The date format is: %A, %B %d, %Y
The time format is: - %I:%M %p

They are right next to each other, with separators on either side. For the time format, the dash creates a separation between them. I was able to get a best choice for my operating system by combining the simplicity of Ubuntu with the functionality of Xfce. There are some features in Ubuntu I could not remove, such as the helpful information that appears when hovering over a panel launcher.

Opening an application with one of the launchers on the leftmost panel adds an icon to the larger panel right next to it. The open applications can be selected from. In the settings for the item on the larger, second panel, called Windows Buttons, uncheck Show button labels so there is no text. Uncheck Show handle to remove the space at the top of the panel. There is a little bit of extra space at the top of the panel if you don't uncheck that.

In order to edit a panel, right-click on it. You can choose from existing panels. In my Xfce installation there were two at first. There was one at the bottom. I used that for the one of the left, and changed some of the default applications. You'll find the option to edit the panel from among the various options in the list, from right-clicking.

Installing Dolphin to Remove File Manager Popups
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When the mouse is hovering over certain items in the file manager, a popup might appear. dolphin does not have that. It's another file manager. It can be installed with:
sudo apt install dolphin.

When you want to add an application to the panel (I used the leftmost panel), There is a program called Application Finder. You can begin typing the string of it's name to find an application to add. Once it's visible click and drag it onto the panel. You might have to do this twice. It appears that the panel or Application Finder might not be in focus, and doing it once causes them to be focused. Then the second time will work.

If you cannot find Application finder, try:
Right-click panel, Go to Panel > Add New Items.
Select Applications Menu.
That will add Applications Menu if it is not already available.
From Applications Menu, go to Accessories > Application Finder.