The following diagram might make you rethink never considering what amount of english you need. In the diagram below, you have to shoot the 4, then the 5. The 7,8 &9 were left out because they don't matter right now. How do you know how much spin or reverse to put on the cb to be sure to hit the 5 after making the 4?
Shots like this is where it really pays off knowing what does what. Here, a stun shot will bring you across to the side pocket. We want to come down 2 diamonds past the side. So, all you have to do is set up for a stun shot, and then add two tips of left english. You will come right into the 5 to break it out.
2 tips of spin at different speeds would yield different results. So would 2 different cues, or tables, or 2 different players.... so I dont see that shot as being so cut and dry. What if the cluster was only an inch or so lower or higher? Would you need to adjust by another half tip? Nothing wrong with that if that works for you, but I tend to go by feel and speed. Meaning that if the cluster was an inch or 2 lower I may hit softer to open up the angle(as opposed to more english). More draw would also open up the angle.