The head is exactly the same as the light vertical, the difference is in the column. The two taper roller bearings for the spindle can be greased with a lithium type high melting point as used in older car wheel bearings. Be sure to be sparing with the quantity, you need at east 50% air space in the quill-spindle assembly to allow the grease to be pushed away from the rollers when the spindle first starts or there will be churning which caused an unwanted heat build up. Preload should be the least possible, or running at top speed will also overheat things. 15 minutes of high speed running should only make the spindle luke warm. The grease will automatically distribute itself onto the moving parts and would only need to be inspected every two or three years.
See the excellent website “lathes UK” and look under Senior in the mills section.