This set has enough Main Power Up to bring the Splattershot Pro and the Splash-o-matic up to 49.99 damage and 33.33 damage respectively.
Compared to the .96 Gal and the H3-Nozzlenose, the Splattershot Pro suffers from being too generic and not having any defining strength. Therefore, maximizing damage to get consistent 3-shot kills from range with 2-shot kill potential is important for the Splattershot Pro to compete with guns in the mid-range category that are stronger overall.
Comparing its high run speed and 3-shot burst, the H3-Nozzlenose can engage in hit-and-run tactics while the Splattershot Pro has no option to retreat once it is engaged in a fight. It also doesn't help that the .96 Gal has better damage and range. This puts the Splattershot Pro in an awkward position where it can struggle to get in range of enemies. Run Speed is added to make up for this weakness, giving the Splattershot Pro the ability to chase an opponent down and move around while firing. Lastly, the two remaining slots are filled with Swim Speed for more mobility overall.
The Splattershot Pro is my favorite gun in the game but it is weak in all categories. This set intends to play on its generic traits to make it a more versatile weapon in the mid-range category than the .96 Gal and the H-3 Nozzlenose could ever hope to be.
I encourage you to try this set for yourself and see how it feels. This set can also be used with the Splash-o-matic due to both guns needing the same amount of Main Power Up to reach max damage.