I haven't looked into the code. It actually needs a 3rd party audit to make sure it is all legit.
(+1)
The idea is clever however it will never work because after a month or so, the pot will get so big someone will basically program a bunch of bots to get the pot.
(+1) to this and Hhampuz statement as well. I would say making a time based fee would solve it. For instance like in intial time of round say Day1 (just taking day as example) there is no fees. The next day it is 1% . Something like this.
Anyone would stay away front playing this watching huge fees (20%). My suggestion would help out this problem. Also I would say mention somewhere that TX fee is cut from the jackpot.
Hope you will thing about it and make changes accordingly which is comfortable for you and the players as well.