interaction design - What is the best graphical interface for inputting a list of pairs?

I want to create a graphical interface for inputing skill build orders for an RPG game. A skill build is an ordered list of (skill, number) pairs, like this ^{(see footnote)}:

(A x1) -> (B *) -> (C x2) -> (A *)

I want to create a graphical interface that can add items to this kind of list, preferably in any position of it.

The main idea I am having now is to make some sort of drag-and-drop interface, with icons representing the skills

current build = (A x1) -> (B *) -> ...
-----------------------------------------    
amount: [ 1 | 2 | 3 | 4 | * ] (radio buttons or drop-down selector)
skills: +---+  +---+  +---+
        | A |  | B |  | C |
        +---+  +---+  +---+

Clicking an icon would add the item-number combination to the end of the list (the most common place to add things to) and dragging it to a spot on the result list would cause it to be inserted there instead.

But I imagine having to do multiple clicks to select the number and the icon would be awkward. An alternative might be having a button for each possible pair:

+----+  +----+  +----+
|A  *|  |B  *|  |C  *|
+----+  +----+  +----+

+----+  +----+  +----+
|A x1|  |B x1|  |C x1|
+----+  +----+  +----+

+----+  +----+  +----+
|A x2|  |B x2|  |C x2|

+----+  +----+  +----+
//and so on

But then I think it would get way too cluttered.

What is the best way to input such a list of pairs?

Are there any places where a similar problem was solved and where I can take inspiration from?

Some design considerations:

• 
  

  I have 4-5 skills and the numbers range from 3-5 (and the * wildcard)

  
  
  


• 
  

  Some numbers (1 and *) will be selected more often then others (2,3,4). All skills are equally likely to be selected.

  
  


• 
  

  If we choose an asymmetrical design, skills should be prioritized over numbers.

  
  


• 
  

  I am primarily interested in obtaining a fast and clean workflow. It is OK if the final result ends up a little complicated or unintuitive.

  
  
  
  
  
  • This is not intended to be the default interface. I want this to be faster then the simple but slow interface where each skill is entered manually for each level.
  
  
  
  

---

For the curious, a pairing like

(A x1) -> (B *) -> (C x2) -> (A *)

can be interpreted as

As a first priority, level up A once

As a second priority, level up B whenever possible
As a third priority, level up C twice
As a fourth priority, level up the remaining levels of A

The main reason for using this is because describing directly what skill to take at each level is longer and less clear:

A, B, C, B, C, B, A, B ...  // this is simple, but less clear