2 leaps per 8 years
In this though experiment,
we position 2 leap days in a row at the end of 8 years of 365 days.
The aim of this is to support the 7 day week advancing more evenly.
Each new year advances the day of week by one day,
as 365 days = 364 days (52 weeks of 7 days each) + 1 day.
So if at the start of an 8 year period, the 1st of January is a Monday, then the next year it’s a Tuesday, and so on, until the 8th year where it is a Monday again. Then because the year finishes with two extra leap days, the next year starts on Thursday, and then Friday and so on.
This connects directly with the Octaeteris the period of eight solar years after which the moon phase occurs on the same day of the year plus one or two days.