Very good question.
I would suggest to split up the "Top 100" not only between SS and EM but also between DMD plus maybe Electronics from 1985 to 1990 AND ALSO to create another list for Electronics before 1990 or 1985.
The DMD machines should have at least 50 ratings instead of 15 before they get into the list.
15 votes for the "older" machines should be OK.
The EM-List requires only 5 votings which seems a bit funny but on the other hand there are very few ratings anyway so it's difficult.