Unfortunately, I would say that there is no way to optimize. Although it is possible to kill all 3 bosses in the same cycle, you will only be able to get 1 reward each cycle, and as long as you don't get the reward of all the bosses you killed, you won't be able to kill them again.
My tip is: if you want to start, for example, with Jaul, wait until the 5th day to see if he appears. If he doesn't appear, kill the boss that appears on the last day.