When the tablet is turned around (inverted with line b1at bottom on side b) we can expect to perceive some differences in the glyphs. Maybe we have to follow the nakshatra side - that was my perception when moving from side a to side b on the Mamari tablet.

According to the Gregorian calendar July 1 was visible in the nakshatra sky (close to the Full Moon) at the glyph where the night time sky (ragi) had changed place with the nuku figure, at heliacal December 31.

Ragi Ra'i, T. 1. Sky. 2. Palace. 3. Prince. Henry. 1. Sky, heaven, firmament; ragi moana, blue sky. 2. Cloud; ragipuga, cumulus; ragitea, white, light clouds; ragi poporo, nimbus; ragi hoe ka'i cirrus (literally: like sharp knives); ragi viri, overcast sky; ragi kerekere, nimbus stratus; ragi kirikiri miro, clouds of various colours. 3. To call, to shout, to exclaim. Vanaga. 1. Sky, heaven, firmament, paradise; no te ragi, celestial. 2. Appeal, cry, hail, formula,  to invite, to send for, to notify, to felicitate, precept, to prescribe, to receive, to summon; ragi no to impose; ragi tarotaro, to menace, to threaten; tagata ragi, visitor; ragikai, feast, festival; ragitea, haughty, dominating. 3. Commander. 4. To love, to be affectionate, to spare, sympathy, kind treatment; ragi kore, pitiless; ragi nui, faithful. Churchill. Modoc, a language used on the northwest coast of North America: 'A single word, lagi, was used both for the chief and for a rich man who possessed several wives, horses, armour made of leather or wooden slats, well-filled quivers and precious firs. In addition to owning these material assets, the chief had to win military victories, possess exceptional spiritual powers and display a gift for oratory.' (The Naked Man)

However, in rongorongo times the true position of this birth ought to have come 4 nights later, in He Anakena 10 (190). 12 * 19 = 228 and 1 + 228 = 229.

The Arkab pair of β stars in Sagittarius were considered as the only vulnerable spot of Achilles, and his outstretched leg may have corresponded to the outstretched leg of Schemset and possibly also to that in Ga7-33 (in what could be the 28th night of Mauri).

"β¹ and β², Arkab and Urkab are from Al 'Urkūb, translated by Ideler as the Tendon uniting the calf of the leg to the heel, and this coincides with their location in the figure on modern maps, as well with their Euphratean title Ur-ner-gub, the Sole of the Left Foot ..." (Allen)

We remember the Cancer stars Heap of Fuel, Tegmine etc from the time of their heliacal positions. Instead of 10 days beginning beyond nakshatra Castor (at Gb1-3) it seems reasonable to continue with 'one more' night to nakshatra Al Tarf (The End) - and to the midnight culmination of Ras Algethi (α Herculis). Or possibly to move ahead even further:

Gb1-14	Gb1-15	Gb1-16	Gb1-17	Gb1-18	Gb1-19 (248)
Gredi (307.2), σ Capricorni (307.5), Alshat (307.9)	Al Sa’d al Dhabih-20 / Ox Herd Boy-9	Okul (309.6), Bos (309.9) Arneb	ο Capricorni (310.2), θ Cephei (310.5) Alnilam	Rotten Melon, φ Pavonis (311.2), η Delphini (311.4), ζ Delphini, ρ Pavonis (311.7) Phakt	Rotanev, ι Delphini (312.3), τ Capricorni (312.6), κ Delphini (312.7), SVALOCIN, υ Capricorni, υ Pavonis (312.8)
	DABIH (308.0), κ Sagittarii (308.1), Sadir (308.4), Peacock (308.7)
Al Tarf (124.3) Ras Algethi	χ Cancri (125.2), Bright Fire (125.4)	Avior (126.4), φ Cancri (126.8)	ο Ursa Majoris (127.4)	Pushya-8	Āshleshā-9 / Willow-24
				υ Cancri (128.1), θ CANCRI (128.2), η Cancri (128.5)	π¹ Ursa Majoris, δ HYDRAE (129.6), Al Minhar al Shujā, Museida (129.9)

My imagination points at the pair of upside down haati (sacrificed limbs) and to the following hakaturou fishhook and says the upside down southern hemisphere will here receive a new Moon (2) land, drawn up from the deeps. Because here the Sun was like a Rotten Melon and the Nose of the Hydra (Al Minhar al Shujā, σ Hydrae) could be seen close to the Full Moon.

North of the equator there was a flying (feathered) serpent (dragon) and south of the equator there was a swimming serpent (hydra). In the world between there was the Crab (or Turtle):

... It is the most inconspicious figure in the zodiac, and mythology apologizes for its being there by the story that when the Crab was crushed by Hercules, for pinching his toes during his contest with the Hydra in the marsh of Lerna, Juno exalted it to the sky; whence Columella called it Lernaeus.