For smooth vertical movement of a rectangular plate on rods, linear bearings or bushings are recommended, as they allow for easy motion without binding. The setup can include opposing bearings on either side of the plate, with a load capacity suitable for approximately 8 kilos. Aluminum or stainless steel rods with diameters between 5/16" and 1/2" are appropriate for this application. Resources like McMaster Carr or Grainger can provide various options for linear bearings. This approach ensures reliable performance and longevity for the intended use.