winter					4 * 25 = 100
	Ye1-1	Ye1-2	Ye1-3	Ye1-4
summer
	Ye2-1 (120)	Ye2-2	Ye2-3	Ye2-4 (180)	Ye2-5	Ye2-6
					10 * 20 = 200
	Yf1-1 (240)	Yf1-2	Yf1-3	Yf1-4 (300)
winter					4 * 25 = 100
	Yf2-1 (325)	Yf2-2	Yf2-3	Yf2-4 (400)

Following my intuition (based on much experience of course) I can read that there are 10 glyphs with hidden tops. I think these indicate the lightest sun part of the year. Giving 20 days per glyph it becomes 200 days. The rest of the year is then distributed evenly between 4 + 4 glyphs (signifying the night time of the moon).

I have then tried with 25 (the number of Saturn - the opposite male character compared with the Sun) to define a total of 400 days. Had I instead chosen to give these 8 glyphs 20 days each, the result would have been:

winter					4 * 20 = 80
	Ye1-1	Ye1-2	Ye1-3	Ye1-4
summer
	Ye2-1 (100)	Ye2-2	Ye2-3	Ye2-4 (160)	Ye2-5	Ye2-6
					10 * 20 = 200
	Yf1-1 (220)	Yf1-2	Yf1-3	Yf1-4 (280)
winter					4 * 20 = 80
	Yf2-1 (300)	Yf2-2	Yf2-3	Yf2-4 (360)

I think this alternative is more reasonable. The simplest solution should be chosen as the basic reading, and to have 20 for all glyphs is to prefer.

Moreover, summer is still living at Yf1-4. After the death of summer sun it will look as in Yf2-2. Therefore Yf1-4 cannot be at 300, that is too high a number.