7. If we insist that mago in Gb2-10 must be at autumn equinox, then the first suggestion is to say it is at day 266 according to our own calendar, i.e. 266 + 9 = 275 days beyond our own winter solstice. But counting 275 days from Ga1-28 will not land us at Gb2-10, because there are only 266 - 28 = 238 glyphs from Ga1-27. Furthermore, June 21 is our summer solstice.

January 31 31
February 28 59
March 31 90
April 30 120
May 31 151
June 21 172
30 181
July 31 212
August 31 243
September 22 265
30 273
Oktober 31 304
November 30 334
December 21 355
31 365
201 35
Ga1-27 (*92) Ga1-28 (**1) Gb2-9 Gb2-10 (266) Gb2-11 Gb2-12
June 21 22 236 22 September 23 24 25
242

Counting backwards from June 21 we will reach spring equinox 172 - 80 = 92 days earlier:

63 27
Gb6-25 (408) Gb6-26 (*1) Ga1-27
92

Next we can go back a further 80 + 9 = 89 days. 409 - 89 = 320 should be at winter solstice north of the equator. The glyphs seem to agree, and we are at the end of the line (b3) which has no sign of  henua:

85 63 27
Gb3-29 (320) Gb3-30 Gb4-1 Gb6-25 (408) Gb6-26 (*1) Ga1-27
89 92
181 (= 172 + 9)
South of the equator North of the equator
autumn equinox 266 89 = 266 - 177 spring equinox 80 (89)
Achird 266 + 11.7 = 277.7 92 = 358 - 266 Achird 89 + 11.7 = 100.7
winter solstice 358 = 266 +172 - 80 summer solstice 172 (181)
Sun returns (Naos) 23 (*122) = 87 - 64 87 Sun leaves (Naos) 202 (211)
Alterf 52 Alterf 240 = 211 + 29
Achir (Regulus) 266 + 153.7 - 358 = 61.7 Achir (Regulus) 89 + 153.7 = 242.7
Alkes 75 = 266 + 167 - 358 Alkes 256 = 89 + 167
spring equinox (Denebola) 87 = 358 + (266 - 172) - 365 autumn equinox (Denebola) 266 (275)
summer solstice 177 = 87 + (356 - 266) 90 = 177 - 87 winter solstice 356 (365)
Sun leaves (Altair) 202 (*301) = 23 + 179   Sun returns (Altair) 16 (25)

By instead counting 266 days ahead from June 21 (winter solstice south of the equator) we should reach autumn equinox at day 172 + 266 = 438 according to our own calendar. This in turn could make us think of Gb6-20 which is 35 glyphs earlier than glyph number 438 (and also 64 + 1 glyphs later than hipu in Gb4-17):

Gb6-17 Gb6-18 Gb6-19 (*466)
Gb6-20 (403) Gb6-21 Gb6-22 Gb6-23 Gb6-24

The position of Gb6-20 can be compared with that of Alterf (λ Leonis) - similarly 35 days before Denebola.

The quartet Gb6-21--24 constitutes a very strong Sign for a new beginning, and glyph 438 could correspond to autumn equinox on Easter Island:

Gb7-24 Gb7-25 Gb7-26
Polaris
Ashvini
31 27
Gb7-27 (438) Gb7-28 Gb7-29 Gb7-30 (*33) Ga1-27
Alrisha (438.2) Alamak (438.7) Hamal (439.5)   58 winter solstice

North of the equator spring is on its way, and hakaariki in Gb7-30 is 33 days beyond spring equinox. But on Easter Island the heliacal rising of Alrisha (α Piscium) is a sign of autumn.

Gb6-20 is evidently 5 days before spring equinox north of the equator which should correspond to day 266 - 35 = 231 from winter solstice on Easter Island.

We reached this conclusion by jumping in thought to the end of side b instead of moving forward from Ga1-28. If we instead should add 266 glyphs to Ga1-27 we will reach glyph 28 + 266 = 294 which is Gb3-3:

Gb2-27 Gb2-28 Gb2-29 Gb2-30 (*350)
Gb2-31 Gb2-32 Gb2-33 Gb2-34 (*354)
Gb2-35 Gb3-1 (292) Gb3-2 Gb3-3 Gb3-4 Gb3-5 Gb3-6
11 12 13 March 14 15 16 17

The date at Gb3-3 ought to be March 14:

June 21 9
July 31 40
August 31 71
September 30 101
Oktober 31 132
November 30 162
December 31 193
January 31 224
February 28 252
March 14 266

This solution seems at first not to very convincing, but if we go on to March 21 it becomes more interesting:

Gb3-7 Gb3-8 Gb3-9 (300) Gb3-10 (**273)
March 18 19 20 21

There is a tamaiti at spring equinox north of the equator it seems to say. 301 - 28 = 273 (equal to the number of days from January 1 to the end of September).