As you know, the average after 1 cycle is 11 people on zero. The average after 2 cycles is 14 people on zero. The average after 3 cycles is 17 people on zero. The average after 4 cycles is 19 people on zero. Now if after phase 1 you have the counter on only 1 or 2 (there's a total 1% chance of this) then it means you might want a fifth cycle.
Optimise the day numbers for each cycle.
There is a 0.545% chance that after the first cycle you reach 30+ people on zero. So, allocate 30 days for it.
If you reach 11 people on zero after the first cycle then there is a 0.509% chance that after the second cycle you have 31+ people on zero. So allocate 20 days for it.
If you reach 14 people on zero after the second cycle then there is a 0.518% chance after the third cycle that you have 32+ people on zero. So allocate 18 days for it.
If you reach 17 people on zero after the third cycle then there is a 0.576% chance after the fourth cycle you have 34+ people on zero. So allocate 16 days for it.
If you reach 19 people on zero after the fourth cycle then there is a 0.564% chance after the fifth cycle you have 34+ people on zero. So allocate 15 days for it.
Complete. Allocate 5 cycles for phase 1 as above. Phase 2 coming next....