My suggested outline for the rules:
1. Whoever runs the pool keeps at minimum $300 of winnings. For example, the winnings are $1000, the host keeps $300. If the winnings are $250, the host keeps the entire winnings.
2. a. If there are excess winnings from item 1, beyond $300 but below returning 75% share value, this remaining sum is saved for a future drawing, but all participants lose their shares and must re-enter at next drawing. The remaining sum will not contribute or affect share value, strictly number of tickets purchased. For example, there are 100 shares paid in at $10 each - this means the remaining value after subtracting $300 would have to average to under $7.50 to be continued on to next drawing.
Eg. 100 shares at $10 each and we win $1000. After subtracting out $300, $700 remains. Divide $700 by 100 shares and you have a return of $7 per share. This is below the threshold so the remaining winnings will be put toward a future drawing.
2. b. If the remaining sum does not allow for the purchase of an even number of tickets, it will be rounded down and remainder goes to host. Eg. $5 remains, $4 is spent on tickets for next drawing and $1 goes to host.
3. If the return amount is 75% or greater per share after subtracting host "fee", the winnings are distributed back to the winners.
Eg. 100 shares at $10 each and we win $1500. After subtracting out $300, $1200 remains. Divide $1200 by 100 shares and you have a return of $12 per share. This goes back to the participating players.
3. a. Winners can decide to donate their winnings to the host (on top of the hosts $300 "fee") or to the next drawing (without reserving any shares in the next drawing)
Something like that. I'm sure I missed some scenarios and I didn't get a lot of sleep last night so it probably isn't coherent, but hopefully gets the point across!