> As a next step I am proposing to filter out the unknown contributors and 
> the contributors with code size <=25 as the FSF is suggesting.

1) The unknown contributors should *not* be filtered.

2) The FSF filters out contributors with code size <= 10-15.

3) It is not a suggestion *from the FSF*.  You may say, "as FSF 
practices suggest".

Anyway, if the SFLC said that even the smallest contribution matters, 
you should abide to that.  On the other hand, you can ask Eben Moglen if 
there is a case from which the "tiny change" practice was derived, and 
submit that case to the SFLC.  But for now, you should not filter out 
anyone (especially unknown contributors!), unless of course you wish to 
concentrate on major contributors first, and tackle minor contributors 
later.

Paolo