1 in 3
For the benefit of the ppl that don't bother to read entry forms, here is an excert from the entry form to explain dans question.
Assuming That Each Division has a Minimum of 9 Entries Each, The Top 3 (Based on Pinfall) From Each Division, Will Progress To Stage 2.
i.e. 1 in 3 Entries Per Division Progress. IF A Division Has Less Than 9 Entries, The Number That Progress Will Remain A Ratio Of 1 in 3 And The Next Eligible Bowler From The Division With The Most Entries, Will Progress To Stage 2. THIS WILL BE WORKED OUT ON THE DAY.
e.g. If the Open Male Div. Has 12 Entries And The Open Female Div. Has 6 Entries, The Top 4 From the Open Males Will Progress to Stage 2.
Now, this was based on 36 entries, 9 per division, if we have 24, it will 6 per division. Thats how 4 open males came about coz, they have the most entries.