Small world, I opted for a Gosper curve myself, but when it got too big, cut out specific pieces and connected those.
It gives everything a uniform look while allowing to fill the space in a different way.
That sounds super interesting, do you have a link?
Not the person you asked, but look up "Hilbert Curve" on Thingiverse, Printables, or Thangs and I bet you'll find somebody who uploaded a marble run with more information for you.