glyph numbers and days are counted from Ha1-4
Hb9-39	Hb9-40	Hb9-41	Hb9-42 (1099)	Hb9-43	Hb9-44
366 = 1098 / 3			367
Hb9-45	Hb9-46	Hb9-47	Hb9-48	Hb9-49	Hb9-50
368			day 1

368 = 432 (= 1296 / 3) - 64. Counting from Ha1-4 implies there are 63 days at the end of side b and 1 day at the beginning of side a, maybe a method to make the reader realize time does not end at the end of side b.

46 can be explained as the difference between 400 and 354, the time beyond the full measure of 12 lunar months to the end of the 'square of earth'. 46 will therefore carry the meaning of 'beyond light', i.e. a barren Y-time waiting for next birth of light at winter solstice.

64 can be seen as 46 reversed. Glyphs which are reversed mean the opposite of the normally oriented ones, and possibly reversed numbers will also mean the opposite. From winter solstice there is a time of light, a time of 'leaf' instead of a time of 'straw'.

400 - 368 = 32, half 64. Next half will be 432 - 400. From this it follows that indeed Friday is the first day of new light.

But then only 368 - 354 = 14 days remain of those 46 in the dark.