Regarding the 'inaccuracy', see the table below showing the bearing of the sun at sunrise on 20 Mar 2019, longitude W35 20', latitudes from N90 to S90.

You see the bearing is not exactly 09 degrees at every latitude. This cannot be due to refraction, as it is an expected value based on RET. I notice the variance depends on longitude, and I suspect it is due to the problem of finding a circle of longitude that is exactly perpendicular to the (nearly) parallel sun rays striking it.

Is this a fatal problem for RET? No. Does it present difficulties for FET? Yes. To the unaided eye, which is what Zetetics is about, the sun will appear due East at sunrise from every latitude at the equinox. Given that there must be a unique point on the flat earth where the sun is directly overhead, how do we explain that fact?

Remember my point above. Science prefers a theory that gives an approximately right answer to one that gives an answer that is exactly wrong, or which gives no answer at all.

90, 90

80, 90.03

70, 90.07

60, 90.1

50, 90.13

40, 90.17

30, 90.18

20, 90.2

10, 90.22

0, 90.22

-10, 90.22

-20, 90.2

-30, 90.18

-40, 90.15

-50, 90.13

-60, 90.1

-70, 90.07

-80, 90.03

-90, 90