What are you making it for?
Do you just ant the stage presence of firing larger things than everyone else? If so, it doesn't really matter how you make them, because performance isn't what's important.
Do you want the psychological edge of firing big things at ordinary ranges? If so, I'd recommend Drac's approach, because its fantastic for that.
Do you want the performance edge that innately comes with firing larger calibre ammunition, thereby enabling superior range? If so, you have a problem:
Ordinary nerf darts are fired with an equalisation of pressure from inside and outside them, preventing rupture over numerous repetitions. This is one of the reasons that Drac's rockets are more durable - the PETG sleeve bears the internal pressure, and not a pool noodle. However, Drac's rockets are still a flawed system, as they do not have a sealed pressure container. You could improve on this by adding a cap to the PETG wall, then adding an O-ring at the tip of the barrel to ensure a perfect seal from barrel to PETG. This would allow you to ramp up the pressure (for higher acceleration), and increase durability (by having a sealed pressure vessel).
As for the head, use something a bit heavier, like half a stress ball with a weight inside. A rocket (even one with perfect fins) relies on the weight distribution being near the nose, otherwise you get spiraling and pretty bad inaccuracy. If you get a decent weight at the front (probably 50 - 100 grams), and no fins, your rocket will still fly true.
Overall, rockets do what MEGA darts should have done - add mass, so that range can be improved.
I've always wanted to be a pilot. Then I'll have an excuse to keep my head in the clouds.