The "angle back" typically seen on a wing is due to the change in wing thickness as the span increases, as much as anything.
It's easier to do the manufacturing of the parts. The percentage of the chord of the surface relative to the airfoil at that point remains constant, while its actual chord diminishes out along the span.
On a model, it probably doesn't add or subtract anything from the perceptible performance to have them tapered as per full-scale or constant chord ..... easiest.
Unless you are looking for full-scale similarity, of course.
The most likely problem is too much deflection creating unneccesary drag or too-active a response.