Hey Bluebell,
We have 7 beds of asparagus plants grown in 3 different spots of our garden. Some in direct sunlight and others in a more shadier, sheltered spot and some in between direct and shade depending on the time of the day.
Those in direct sunlight are definitely more vigorous, my best bet would be in direct sunlight and if you are able to plant them in a good load of composted animal manure, I reckon it would do just great.
Alternatively, if you can afford the space, why not grow in the 2 different spots…. Green asparagus are definitely worth growing.
Just my humble opinion.