I suggest to not use round numbers, first come first served.
Was it intentional that there is no clause preventing non-unique guesses?
First come first served is preventing a valid similar guess as someone already posted or it will be invalid.
This started last year just for fun and very simple rules but people kept suggesting all kinds scenario's so that's why I added some more.
No matter what I'd like to keep the right for any final decision on the outcome in a reasonable way.
With 300 CBX on board no one knows how serious it could get since the price of CBX has been several dollars each on the top. A lot can happen in a year.