After reading The Goetia of Dr Rudd, I have started to pay attention to things that I previously did not before, like the ruling angels of the hour because in that book it mentions about first invoking the ruling angel of the day and hour prior to evoking the specific spirit one is trying to contact, so that it will show up and pay you respect. The ritual it shows for how to do this and for erecting the Temple correctly by writting the names of the hour and the angel in the circle comes from the Heptameron, as I am sure most of you know and also know that the invocation in the Goetia also comes from it.
My point being, is that it makes perfect sense to do this because the place of working, is the Temple, which means a place in time. So by being in the right place at the right time and gaining the assistance of the ruling forces of that time would assure success. I have not tried it myself yet, but would love to hear of anyones experience with this method of working and how it compares in effect to other different approaches.