Hey Gaieus,

Did you ever figure our the difference between your SU model and twilight(kerkythea) models? Was it just a matter of geolocation and magnetic declination?
I made a simple sundial model in SU and verified Google's equation of time to be accurate relative to the accepted equation from Duffie and Beckman.

EoT = 9.87sin(2B)-7.53cos(B)-1.5sin(B) , where B =(day#-81)*(360/365).

Based on this, the sun should be in the right point in the sky at all times in SU.

nick