What is the horizon? If it can be ambiguous in astronomy, with the complications of atmospheric refraction and extinction, and geocentric vs topocentric positions, astrology makes it even murkier. Is it the boundary between sleeping and waking, or the moment we assume our mask and enter the public stage? What is temperament? How conscious are we when we wake up? Is waking itself the assumption of a mask?
My usual house system is Campanus, which makes the horizon the 1st House cusp regardless of how far north or south of true east the Ascendant is, but I am attracted to the possibility that Meridian houses might give a more direct indication of the Zodiac’s orientation to the cardinal directions on the local landscape.