Same here on the getting the coil spring to seat on top. You would think there would be an obvious groove or indention for it to sit in to but apparently not and it's almost impossible to look up into the cavity to see whats going on. Moved mine around a few times and really never knew 100% that they are where they should be...got them centered in the cavity so I guess thats close enough. They really are a pain. The upper control arm bushings were nothing compared to the coils.
they sit in a pocket in the top and the lower end of spring sits in a groove in the lower control arm with the end of the spring butting up against the end of the groove.
Yip- it's getting the spring to seat up top that's a pain in the buttocks- at least on a 78. There is a "lip" of sorts on the top side that has zero margin for error that stabilizes the top of the spring. Getting it to sit the lower control arm is easy and exactly as you indicate. The best way I have found is to drink copious amounts of beer, curse excessively, cross fingers, throw chicken bones, pray to all appropriate deities if that's your thing or God Almighty, and crank that sucker up.