I am also working on a game, I am recreating the platinum game for pc.
I wrote a program that can pick textures and 3d models from the .nds file and after looking at the models the angle is around 45 degree.
Entities are drawn with a bildboard effect, fences and flowers are baked into the model with no angle at all.
But only using the angle will not give you the same look and feel.
You have to calculate the correct projection matrix.
Take a look at the result.