In my current creative mood I see several promising leads, for instance how the central 'tree' in hua poporo is alluding to the male member:

It stands up, while in Qa1-20 and Ga4-7 the 'threads' allude to woman:

  

The 'string' of the horizon stretches like a thread from west to east, yet also like a radius (beam of light) all around the circle defined by the male sky and the female 'cauldron'.

"Yet even in history itself, certain elements persist, and provide a solid anchorage to which the myths can attach themselves. Looking back over the themes that have been the driving force of the present study since the outset, we can perhaps say that certain modalities of culinary technology are of this nature ...

The Tupi made pottery and practised cannibalism, that is, they exercised a technical skill and followed a custom, which were either unknown to, or forbidden by, the Ge.

The Bororo were potters like the Tupi, and non-cannibalistic like the Ge. Moreover, whereas the ancient Tupi used to smoke or roast meat over a low fire, the Bororo usually boiled it ... The Bororo also eat corn in the form of a mush, as the Tupi did, and still do, in those areas where they survive. In this respect, these two communities are in opposition to the Ge, who ... 'drink pure water and do not like the corn mush, of which the Tupi are so fond' ...

In Salish society the earth oven was associated invariably and exclusively with the female sex. The Flathead considered everything to do with digging roots or edible tubers and caring for the pit women's work. 'In fact, the presence of men was tabooed ... lest bad luck and famine overtook all' ...

The Ge, unlike their Bororo and Tupi neighbours, used and still use, a kind of earth oven ... Stones, or fragments of anthill of comparable hardness, are heated on a wood fire until they are red-hot; the site of the fire is then swept, and on it are placed green leaves, to serve as a base for a round, leaf-wrapped pie, more than a metre in diameter, made of manioc with a meat stuffing. The still scorching stones or anthill fragments are piled on top (or placed underneath) ... and the whole thing is covered with old matting and earth dug from the fire area; the general appearance is that of a funeral mound ..." (The Naked Man)

Sun and moon being intertwined according to the rongorongo calendars (as I read them), makes me consider the differences between hiro and hiri:

To 'rise in coils of smoke' and to 'hover like a bird' implies the vertical dimension. Hiri is vertical, while hiro is horizontal.

Three or other odd number of cords are plaited (hiri) into sennit. The word 'twine' (hiro) implies 'double' (twin).

To plait tresses (hiri) is a high activity - located at the top end of the body, at the head. To roll (hiro) by the palm of the hand upon the thigh is a low activity.

The vertical and male hiri is based on 3 or other odd numbers of cords, the horizontal and female rolling movement in a twisting hiro basically has 2 fibres.

Sun has 3 'females' and moon has 2 'males'. Fibres are woody and hard, cords are threads and pliant.

The G and K calendars are similar, yet different. There are 2 more periods in G than in K, due to how at autumn equinox we find period 16 in K, while in G there are 3 periods (16-18). Reading numbers only (disregarding what the glyphs look like), we can draw the tentative conclusion that the K calendar is based on the moon cycle, while the G calendar is based on the sun cycle.

At 15-16 (Otua) in the moon cycle we have the final:

Atan defined the 17th night as He Ohiro, the new moon.

The Mamari moon calendar is based on the measure 8. There are 8 periods in it and 8 is also used for the number of glyphs in each period:

With the end of the 3rd period, at Ca7-16, the measure is 28 - suggesting the number of sunlit moon faces in a month. With the end of the 4th period, at Ca7-24, the measure is 36 - alluding to the how the year is divided in two halves. 3 * 8 = 24.

10 glyphs in the 5th period suggests the downfall of the sun (vero). 3 * 8 + 10 = 34, the number of periods in the G calendar:

The 2 last of the 34 periods have no end-of-period glyphs, i.e. in a way are extra-calendrical.

The G calendar has 18 periods in its 1st half, not 16 as in K:

G therefore ought to illustrate the solar year, while in K number 16 at the middle suggests moon. Yet both calendars, of course, have sun and moon intertwined.

Between the moon calendar of Atan and the calendar for the year in K there is the common factor 16 in announcing the halfway station.

Atan has 30 nights in his month, while the K calendar has 32 periods, the 2 last of which have no end-of-period glyphs.

G and K have different types of glyphs, e.g.:

8 glyphs in G and 6 in K. The sun-oriented G calendar has 8 suggesting moon and the moon-oriented K calendar has 6 suggesting sun.

The member at left in Ga4-7 represents the sun, while the member at left in Ka5-4 represents the moon.

Hau tea in Ga4-7 presumably indicates the a.m. sun, while in Ka5-4 hau tea has two eyes - probably referring to p.m. sun (i.e. in a way the moon). 1 is male, 2 is female.

While the right part of Ga4-7 suggests dry and dead branches, the right part of Ka5-4 instead seems to illustrate a tree full of life (or rather: a canoe ready for launching). The flourishing sun meats his end at midsummer, and beyond that moon has her best season.

Let us compare Atan's calendar with the K calendar:

Obviously, Atan has 27-30 in two pairs: o ari, o ata respectively a raga, a tai. Maybe the K calendar should have a similar structure:

Quite possible. Similarly, we can rearrange the 1st half of the K calendar according to the suggestions of Atan: