I'll throw in some stats for you for the hell of it as well if you want:
supposed outcome of 32 players, 8 players auto-win pools and we are left with 24 players, in 4 pools of 6. This means a total of something like 21 sets per pool, making a total of 84 sets.
16 man double-elim pro bracket works out to about 30 sets
16 man single-elim amateur bracket works out to about 16 sets.
My system means a total of roughly 130 sets being played.
Take a look at alternatives:
top4 go through:
32 total, so 28 players in pools, meaning 4 pools of 7, which is 28 sets per pool, which is 112 sets total.
if we add on the brackets as well, that comes to 158 sets total.
what we have now:
32 total, 32 players in pools, meaning 8 pools of 4, which is 10 sets per pool, which is 80 sets total.
24-man double elim bracket means about 46 sets total.
this gives us roughly 126 sets being played; the top 8 auto-win cuts just enough time down that we can actually do 2 brackets in almost the same amount of time it takes to do one!
so why is 8 our "magic number" for balance?
if the idea is to reduce time and give lower-skilled people a chance for a quality bracket experience then we will need more than 8 people for it to achieve its purpose.
Because when you optimise things, there's a specific point at which you have an optimal amount of x and an optimal amount of y. 8 just happens to be that point.