Being the smallest machine it uses the smallest rubber feet. 5/8, but I do like to sometimes use the larger 3/4 because it gives whatever you set the machine on some more protection.. 3/4 would be for the larger 6, 8, and 9 Victrolas.
By the serial number on the metal tag mounted on the side of the case. It will look something like VV-IV 123456 You can look it up online or send it to me and I can decode it.