BG's system has 12 as a base for 1 pt. If I understood correctly, for each additional player, it goes up 4%. I'm not sure why he did a base of 12. Both of our starting points are completely arbitrary, so one isn't better than the other. It's a distinction without a difference. I wondered, and maybe he will address this, if he did that because 12 happened to be our smallest tournament. If that wasn't it, I'd love to know why start at 12.
The system I referenced earlier uses base 12 because that is the average field size for that league (over all seasons), plus the minimum and maximum field sizes for that league are restricted to between 6 and 18 players (events with fewer than six players do not count, and two tables of nine players is the cut-off for maximum participation in an event). Other similar point systems used will have a different base number, which is typically based on average field size for those league games. One advantage of using the average field size as the base number is that points scored from one year to another will have more relevant comparisons, even as the field sizes change over time (either increasing or decreasing). This is important when comparing current performance to years past, or when determining awards for cumulative performance over several seasons (especially if average attendance fluctuated over that time frame).
However, the system I used to score your player results used a base 16 because that was your average attendance for the rated season (ranging from 11 to 23 I believe, going just from memory). It was relatively easy to create a 16-base system that followed our points rules and then apply it to your data.
I think the system works best when the baseline number is either the average or median (midpoint) field size. The point ranges from baseline to smallest and largest should be similar, and not skewed in one direction or the other.