Send general A, wait until he reaches the spot in the screenshot (can be upto 6 seconds after, but not before he turns to the upper right corner) then send all the other generals.
From
A to
C31 - 100 Cultist, 100 Firedancer
*BLOCKING NORMAL: Normal: 1R (1R) 20s
From
B to
C34 - 70 Cultist, 50 Shadowsneaker, 80 Firedancer
*BLOCKING NORMAL: Normal: 79E 121C (-) Min 100s
From
C to
C31 - 99 Cultist, 100 Firedancer
*BLOCKING NORMAL: Normal: 126E 74C (-) Min 100s
From
D to
C35T2 - 80 Cultist, 120 Firedancer
BHG: 153B (153B) 1r, 10s
MMA: 134B (134B) 1r, 10s
From
E to
C35T2 - 56-72-97 Firedancer
MMA: 22R 1M 1S 1E 191C 1B 1LB 1XB 1K (0R - 1R - 22R) 1r, 30-40s
It takes 13-14 seconds for general B to reach his own target camp's area of influence since the moment general A starts his combat, and A will block his camp for 20 seconds (1R block).
The marching time for general D, from the moment general B starts his battle, till the moment general D starts his battle, is about 34-35 seconds. The maximum time needed to kill the leader camp, from the moment the block starts is thus 35+10+40 = 85 seconds. The block always lasts at least 100 seconds.
General C needs at least 87 seconds blocking, and the block last at least 100 seconds.
If you are doing this for the first time and any general is intercepted, retire inmediately all generals and you will lose just 1 recruit. You can try again after this general is recovered, or with another normal general placed near, and waiting for him to reach the same spot.