What is the most efficient way to modify each loop iteration?

I’m currently making a blueprint where speed and efficiency is absolutely essential. In the most crucial part of the blueprint I’m running a massive, nested for-loop that I’m trying to optimize as much as possible. A peculiarity of this loop is that I want to include some repeating variations to the looped functions. Here is a screenshot of a simplified blueprint that illustrates what I’m trying to achieve:

The first and third function will be the same each time, but for the second function I want four different input variables that are used in sequence, one different variable used for each loop iteration, restarting after four iterations. I know of several ways to achieve this, but what I’m trying to achieve is to make it as fast and efficient as possible.

Currently I’m using a sequence instead of a loop, and copied the content of the loop four times, with small variations changed for each. This does run fast, but I feel it makes the blueprint four times as big as it needs to be, and also makes it more difficult to make changes to the blueprint, as I have to repeat everything four times. What does the community think? If anyone knows of a better solution I would be very grateful.

You actually notice a speed difference between using a sequence and a 4x loop?

Not from using a loop itself. However, if I am to make repeating alterations to each loop iteration I have to include if-statements (e.g. if loop index 1 use this variable, if loop index 2 use this variable), while with a sequence that is not necessary, provided I connect a unique set of nodes to each point in the sequence. Using a loop with if statements is noticably slower than using a sequence with modifications.