It'll be a cesspit irrespective of any access changes you make. The problems that come from the section are attributable to the entire concept of the forum rather than because of people with low postcount and a recent member date going in there. Moreover, part of the Spam Forum culture has always been a feeling of elitism -- making the Spam Forum more exclusive will only consolidate the feeling of elitism Spam Forum members have, which make them feel important and will bring together the Spam Forum's members in a negative way -- into a faction.
Not sure how elitist 25 or 50 posts would be. I wouldn't go higher than 50, however.























