I never used the Wirings plugin so I can't help you with that but...

I physically solved it, using a trick seen on the forum to solve other problems by positioning a solid inside the objects (in my case a sphere of minimum dimensions)

Don't use a sphere for this. A Sphere is a huge object in terms of vertices and faces compared to for example a Box. If you hover over the object in the top-left catalog window you can see that the default Sphere is 50kB and a default Box 2kB. With 50+ spheres it's no surprise that things slow down a little.
If you really need a sphere then use an Ico Sphere from my DodecagonShapes library. The smallest one is 6kB. Use a color, not a texture.