WITH the LAT NUT correctly set, we compensate for ER....with no LN,
ER = 15 x sin Lat x 1.5 = 20,
TW = 10 x sin Lat = 8
Total ERROR -28 (both negative)
So at the start (N60 E010).....090G, at the end (N60 E020) 062G.....so the mean (which we need) 076G.