Here’s another brand of pen that I am enjoying using with Spirograph and Wild Gears.
The ink flows smoothly, and there is no problem with the size of the holes even on the old Spirograph with its smaller holes.
This pen doesn’t come in as many colors as the felt pens I’ve recommended for Spirograph before.
But it feels solid, not flimsy, and is pleasant to use.
You could also try the Needle-Point version (left), which looks like it has a finer tip, and comes in a package of 8 colors.
If you try either of these, please let the rest of us know how you liked them by leaving a comment.