Speed up boosts stacking

[Bluu]

Has anyone tested the best combination to have optimal round speed without wasting precious slots?
Attack and defence are pretty easy to test but speed is giving me a headache

 

[8BitBeatDown]

I had done a little research on if the speed reduction from Ninja Squid was canceled/surpassed by Swim Speed Up, and the results were far too inconsistent to be considered conclusive.