Frugal Usenet is on the same backbone as Usenet.Farm, so a better block account option would be Newsdemon on the UsenetExpress backbone. Apparently the Frugal Usenet year plan comes with a BlockNews block (Omicron backbone) as well, which seems to have a retention length closer to that of Eweka.
Edit: My mistake, only the Frugal Usenet bonus server is on the Usenet.Farm backbone.