No, the strings work better for every type of dart so long as you adjust it, test, adjust it again, test again. Until you find the setting that works for that particular dart.
The device without strings was to show that I can get a positive result without strings, and without any twist in the design. I managed to accomplish that with one of the designs, but not the other.
The spiral hole pattern that is commonly used for paintball to accomplish the same effect probably didn't work because it's not a good surface to print. It would probably work fine as a machined feature, and that reflects some testing torukmakto4 did two years ago with looooong barrels with porting near the end.