I found a similar loose fit when assembling earlier. There’s 1 bolt in each of the middle joiner and middle end parts. It actually increases tension quite a bit as you tighten it. I tightened it a bit and it made the fit perfect.
The parts on mine that I’d like to be a little tighter are the roller F assemblies. All the bearings are in contact but I’d like there to be just a little more tension there.
If I keep my thumb against one of the bearings on the roller F as a brake and slide the roller along the conduit, there are places when the bearing will stop turning and just slide along the conduit. I’d prefer a tighter fit than that but tensioning the roller F doesn’t seem to get rid of it completely.