thank you all for your comments! I was not really looking at doing it as a way to give away items - I do that in the collectible section from time to time as both free and paid raffles.
I was looking at as a means for the community to give back to the world outside of the forums - with one lucky person winning half the pot.
Ideas that I liked from the above comments:
1. decreasing the number of slots - ok so not 100 - what about 50?
2. allowing people to put in more - I like this because everyone could put in what they want, what they are willing to risk. The winner(s) are still entitled to half the pot - I say winner(s) because of the next point
3. having more than one winner - maybe do 5 winners? where each get 15% - and this is more than 50% which is the next point I liked
4. increasing reward ratio from 50% to 75% - with 25% going to the charity. I would like to give more to a charity but I understand that if the ratio is too low, there are not enough joining and thus nothing goes to the charity
Idk much about how the blocks work, or their sequence for that matter, but does it guarantee that all numbers from 0-99 show up on the future blocks? Just asking!
1. 50 should be more than enough, but make a minimum-maximum amount of participants so that some people wouldn't be left out by being late on the party possibly.
2. This should work. Though set a limit of maybe 2 or 3 additional slots though.
2. true with multiple winners it would not be fair to make the prizes equal in that regard. so possible set limit on price per entry - but maybe allow people who want to risk more to be able to buy more than one
3. Nothing to say here
4. If you want, you can try using the 80-20 posted above, and the remaining 5 would be given to a random lucky winner again (everyone including the 5 winners has a chance), or redistributed to the ones that lost, though that amount is low as hell by then, so the former could be the best option.
There's a chance that no more than 50 people would join though, so adjusting some stuff there could possibly work. You can also try out what you did in the past, collectibles, add that as a win or something. Pretty optional, like only the 1st or 2nd winner could have them. Or add that to the guy who would win the 5% I said above.