GLS Secretary David Leighton explains the GLS Circuit Factors

Basically, it's a measure of the strength of the tournament. If the tournament is an A (e.g., it meets the USFA standards for awarding the winner an A rating), the factor is 5. If it's a B, then 4, etc., down to a minimum of 1 (e.g., no bonus for an E rated tournament). The sectional championship gets twice this factor.

The actual number of points a fencer earns for any event is calculated as points = factor * (number of fencers - finishing place + 1). Thus the last place finisher in a B tournament gets 3 points. 

If an event was fenced mixed, as some are, then the women's points are calculated as if they had been in a virtual event, with the same ranking as they finished in the mixed event.

That's pretty much it! I'm certainly open to changes in the magic formula if people want it changed.