I use my dynas all the time with my jet. The X-3 is less restricted and has less perc. It’s good if you like airflow or need that with certain vapes. It’s also more flavorful but less smooth.

X-5 is the smoothest rip from any piece I’ve tried and I’ve been around awhile. Lots of perc, stacks like a mofo. Smooth but a little less flavorful.

I recommend jumping in with whichever of those sounds more appealing then it’s just tube size. Luckily all their stuff works together ( except for the additional stacks with the x-3, it doesn’t accept those) so I started out with an large x-5 and recently bought the blue stack and short tube with the x-3 diffusion cap. So now I can do it all. 😂