For a quite different way of approaching this…
Some time ago I discovered a way to discretize the gyroid using only 1 type of triangle.
You can use this as the starting point for a subdivision mesh, and get a much cleaner and more regular result than you do from an isosurfacing approach
Here’s a definition:
subdgyroid.gh (15.9 KB)
Subdivision distorts the open edges, so here it generates a larger portion, then selects only the inner undistorted part to get a properly periodic unit. There’s a little script I wrote in there that lets it select faces in the subdivided mesh corresponding to particular parent triangles.
There was actually a paper published recently on this discrete form of the Gyroid:
https://www.researchgate.net/publication/336315749_Discrete_Gyroid_Surface
I found it a few years earlier though! :