Until now I have not been able to in a satisfactory way explain why the number of glyphs on the C tablet is 392 + 348 = 740. I was convinced the whole measure 740 in some way referred to a pair of cycles, but although 348 for side b clearly was equal to 12 * 29 there was no multiple of 29 suitable for side a of the tablet.

However, assuming the first day ('day zero') on side a has no glyph, then we should count with 393 days:

'February 22 (53)	23 (420)	24
March 21	22 (81)	23
September 20	21	equinox (265)
no glyph
	Ca1-1	Ca1-2
	koia	ki te hoea
Al Fargh al Thāni-25	*Uttara Bh*ādrapadā-27 / Wall-14	χ Pegasi (2.1), θ Andromedae (2.7)
0h (365.25)	*Uttara Bh*ādrapadā-27 / Wall-14
Caph, SIRRAH (0.5), ε Phoenicis (0.8)	ALGENIB PEGASI (1.8)
Alchita, Ma Wei (183.1), Minkar (183.7), ρ Centauri (183.9)	Pálida (184.6), Megrez (184.9)	Hasta-13 / Chariot-28
Alchita, Ma Wei (183.1), Minkar (183.7), ρ Centauri (183.9)	Pálida (184.6), Megrez (184.9)	GIENAH (185.1), ε Muscae (185.2), ζ Crucis (185.4), Zaniah (185.9)

And then 393 - 16 = 377 = 13 * 29 and 1 + 740 = 16 + 25 * 29.

We can apply number 16 also as the measure from heliacal Tau-Ono to the night when this asterism once again became visible:

135 (May 15)	16
151 (May 31)


Ga7-2	Ga7-3 (172)	Ga7-4	Ga7-5	Ga7-6
θ Cor. Borealis (235.3), γ Lupi (235.6), Gemma, Zuben Elakrab, Qin, ε Tr. Austr. (235.7), μ Cor. Borealis (235.8) ~~Sirrah~~	φ Bootis (236.2), ω Lupi (236.3), ψ¹ Lupi (236.7), ζ Cor. Borealis (236.9)	ι Serpentis (237.4), ψ² Lupi (237.5), γ Cor. Borealis (237.7), Unuk Elhaia (237.9)	π Cor. Borealis, Cor Serpentis (238.1), Chow (238.6)	κ Serpentis (239.3), δ Cor. Borealis, Tiānrǔ (239.5), χ Lupi, (239.6), ω Serpentis (239.7), Ba, χ Herculis (239.8). κ Cor. Borealis, ρ Serpentis (239.9)
Ko Ruti 11 (315)	12	13	14	15
*ºNovember 7 (231)**	8	9	10 (314)	11
'October 15 (288)	16	*17 (210)**	18	19
'Tagaroa Uri 15	16	17	18	19 (292)
"October 1 (274)	2	3	4	*5 (198)**
no star listed (52)	no star listed (53) ~~Acrux~~	no star listed (54)	*Al Thurayya-27 /* Krittikā-3 / Hairy Head-18
			Atiks, Rana (55.1), CELAENO, ELECTRA, TAYGETA (55.3), MAIA, ASTEROPE, MEROPE (55.6)	ALCYONE (56.1), PLEIONE, ATLAS (56.3)
			TAU-ONO	ALCYONE (56.1), PLEIONE, ATLAS (56.3)
Vaitu Potu 12	13	14	15	16 (136)
ºMay 9 (128)	*10 (49)**	11	12	13
*'April 15 (25)**	16	17 (107)	18	19
'Vaitu Nui 15	*16 (26)**	*17 (392)**	18 (108)	19
"April 1 (91)	2	*3 (13)**	4	5

At Ga7-21 these 6 stars (tau ono) became once again visible close to the Full Moon, at the eye-catching running into the past figure. The Gregorian calendar arrived here 4 glyphs later at Ga7-25:


Ga7-20	Ga7-21	Ga7-22	Ga7-23	Ga7-24 (193)
Atria (253.9)	Tail-6	ι Ophiuchi (255.3), Grafias (255.4)	κ Ophiuchi (256.2), ζ Arae (256.5), ε Arae (256.8), Cujam (256.9)	no star listed (257)
Atria (253.9)	Wei, η Arae (254.3), DENEBAKRAB (254.7)	ι Ophiuchi (255.3), Grafias (255.4)		no star listed (257)
Ko Ruti 29 (333)	30	Ko Koró 1	2	3
ºNovember 25	*26 (250)**	27	28	29 (333)
'November 2	3	4	*5 (229)**	6
'Ko Ruti 2	3	4	5	6 (310)
"October 19	*20 (213)**	21	22	23 (296)
no star listed (70)	Tabit (71.7), π² Orionis (71.9)	π4 Orionis (72.1), ο¹ Orionis (72.4), π5 Orionis (72.8)	π¹ Orionis (73.0), ο² Orionis (73.4), Hassaleh (73.6), π6 Orionis (73.9)	Almaaz (74.7), Haedus I (74.8)
Vaitu Potu 30	31	He Maro 1 (152)	2	3
*ºMay 27 (66)**	28	29	30	31
'May 3	4	5 (125)	*6 (46)**	7
'Vaitu Potu 3	4	5 (125)	*6 (46)**	7
"April 19	*20 (30)**	21 (111)	22	23


Ga7-25	Ga7-26	Ga7-27	Ga7-28	Ga7-29	Ga7-30 (199)
17h (258.7)	Mula-19	Nodus I (260.0), π Herculis (260.7), Ras Algethi (260.8)	Sarin (261.0), ο Ophiuchi (261.4) ~~Alrisha~~	ξ Ophiuchi (262.2), θ Ophiuchi, ν Serpentis, ζ, ι Apodis (262.4), ι Arae (262.8), ρ Herculis (262.9)	β, γ Arae (263.3), κ Arae (263.5), σ Ophiuchi (263.6)
no star listed (258)	Sabik (259.7), η SCORPII (259.9)		Sarin (261.0), ο Ophiuchi (261.4) ~~Alrisha~~		β, γ Arae (263.3), κ Arae (263.5), σ Ophiuchi (263.6)
Ko Koró 4	5	6 (340)	7	8	9
ºNovember 30	ºDecember 1	*2 (256)**	3	4	5
'November 7	8	9	10	11	*12 (236)**
'Ko Ruti 7	8	9	10 (314)	11	12
"October 24	25	26	27	28	*29 (222)**
Haedus II (75.9)	5h (76.1)	μ Leporis, μ Aurigae (77.6)	ĸ Leporis (78.0), Rigel (78.1), Flaming Star (78.2), Capella (78.4), ο Columbae, τ Orionis (78.8) ~~Thuban~~	λ Aurigae (79.0), λ Leporis (79.6), ρ Aurigae (79.7) ~~Arcturus~~	σ Aurigae (80.4), Bellatrix, Saif al Jabbar (80.7), Elnath (80.9)
Haedus II (75.9)	ε Leporis (76.0), Cursa (76.4), λ Eridani (76.7)	μ Leporis, μ Aurigae (77.6)
He Maro 4	5	6	7	8	9 (160)
ºJune 1	2	*3 (73)**	4	5	6
'May 8	9	*10 (50)**	11	12	13
'Vaitu Potu 8	9	10 (130)	11	12	13
"April 24	25	*26 (36)**	27	28	29

The text has a Rei at Ga7-22, which probably means a cycle has been completed (by alluding to π = 22 / 7). This was where He Maro 1 (152) was close to the Full Moon.

Heliacal RA 255 suggests 100 day were ahead to the 'solstice' - which would come at glyph number 290 + 1.

Hau tea without mata in Ga7-28 could allude to heliacal day 314 in the Al Sharatain calendar. In rongorongo times this was where Alrisha (the Knot) culminated at midnight.

At the other side of the year was the midnight culminatiion of Thuban - the star where the tail of the great serpent was cut by the circumpolar circle, proving it had been the Pole star ca 1 / 6 * 25700 years earlier: