The day formula stored for this lot is Ascendant plus the Moon minus Venus. Unlike most lots in this set the fast body is added rather than subtracted, so the Moon's motion works with the Ascendant instead of against it.
The lot advances about 372 degrees a day: a full Ascendant circle, plus the Moon's 13 degrees 11 minutes, less Venus's degree or so. That is one degree every three minutes and fifty two seconds, marginally faster than the Ascendant itself, and it means the Lot of the Mother is among the handful of points in a horoscope that complete more than one circuit of the zodiac in a day.
The requirement that follows is the ordinary one for an angle-driven lot. The birth time has to be recorded to the minute for the degree to mean anything, and to a quarter hour or so for the sign to be safe.
The choice of bodies is worth noting beside the Lot of the Father. There Saturn and the Sun, the two classical significators of the father, are set against each other. Here the Moon and Venus, which carry the maternal signification between them in the same scheme, are set against each other in the same way, the Moon by sect and Venus by nature. The pair of lots is built on a consistent principle, which is one reason they are usually transmitted together and one reason a variant formula for either should be treated with suspicion.