Share 'how to determine League Winner???'

We have a pretty good point scoring system in place, but was wondering how you guys determine league winners for your clubs?  We keep running into the issue of a guy who wins or places in the top 3 for every mini for 8 weeks losing to a guy who placed worse in each of those minis, but played 12 weeks, so he has more points.  You do a playoff or points averaging with minimum # of weeks required?  …