Holy moley I so missed this thread earlier as I was busy on McLovin day. But you guys are out of control, in a good way.
So clearly you need a software themed month and hardware themed month so anyone can participate. Locking in a particular soap brand or a razor is not going to help things and you'll have dropouts everywhere.
So SE (single edge) September is a very successful theme on other forums that opens the door to some fantastic SOTDs.
Vintage DE, March straight, Coloured razor May, whatever etc
European soap month, vintage, off the shelf (readily available), ready stick February (already Arko month), unobtainium or hard soap month etc
So keeping it simple and open is my decree, if I may