To get better rotation, I created a sleeve for the existing bracket from BamBam Design (Toroidal Windmill https://makerworld.com/en/models/235261?from=search#profileId-251551). A break is added at layer 286 to allow the ball bearing to be placed. The remaining part of the sleeve is then printed. The existing bracket from BamBam Design is a bit too thin. For convenience, I wrapped it with electrical tape to get the required diameter for the ball bearing.