User blog comment:OceanSushi/A Mini Research on the Optimal Maruyu Batch Size/@comment-26154973-20160224100353/@comment-27143098-20160224163113

Hmm assuming that each Maruyu kai always gives +1.6 luck on average, it would mean that in the long run there's ultimately no difference in how many Maruyus you feed at once, since y ou would still get 1.6n luck at the end of the day . 

It seems unlikely that devs would intentionally tweak the success rates to ensure an eventual 1.6 luck per Maruyu though.