Hmm, I would almost be inclined to do it backwards...deposit $52 on the first week of the year, etc., that way you're not hitting yourself with $48 one week, $49 the next, $50, $51, $52...$250 over a 5 week period during the holiday season. BUT that hit can be negated by setting a fixed amount aside for Christmas gift shopping early on.
It is a neat idea. Unless I start making more soon, I can afford to do this comfortably for about 3/4 of the year