That T20 sim is rather pointless ATM, as you can't select the bowlers...
@ Test's - I would have 8 teams, knockout, five/six days, one match series' as you can still win with one bad day, for the final maybe make that a three match series.
@ ODI's - Have two teams knocked out every round, so as follows:
First round, - 1 v 4, 2 v 3 and 5 v 8, 6 v 7
Second Round - winners of 1 v 4, 2 v 3 get byes.
losers of 1 v 4, 2 v 3 verse winners of 5 v 8, 6 v 7.
Third round - winners of 1 v 4, 2 v 3 verse second round winners
Forth Round - Winners of those two meet in a three match finals series.
Home games always go to the higher seeded team at the beginning of the tournament.