So I have just installed Pitbull4 and I have to say I'm impressed, the only thing is that I had to start from scratch with the config. One of the things with Pitbull previously was that the configuration was a real pain. Happy to say that no longer applies :) Configuration is logical and easy (well I thought so haha)
The basic way to look at it is that Pitbull now has "Layouts" that are defined seperate to the Unit Frames. You then assign which Layouts are applicable for which Unit Frames.
Sounds Easy Huh!?!
This is my current UnitFrame for myself
Step 1 Create Your Layouts
In the Layout Editor you create the different types of Layouts you want to use. I broke mine up into; mytoon, mytarget, targets&pet, pet. Best bet is to select the item that closest matches what you want and type in the "new layout" to create what you want.
Step 2 Configure Your Layouts
Easy enough stuff, select the layout you want to edit
The go through the tabs and subtabs to define the layout config such as the colors, fonts, text etc.
Step 3 Assigning Layouts to Unit Frames
Now your done with your layout config its time to assign them to your Unit Frames.
Click the Units link to expand, select the Unit Frame desired and select the Layout on the right. You can then (but I didnt) see frame specific scales/multipliers etc.